US fighter planes and helicopter gunships struck the southern Iraqi city of Basra and the teeming slums of Baghdad’s Sadr City with bombs and missiles Friday as the offensive launched by Iraqi puppet troops against the Mahdi Army, the Shia militia loyal to Muqtada al Sadr, faltered badly.

These air attacks, carried out in densely populated cities, represent another war crime in the five-year-old campaign of aggression and colonial-style occupation carried out by Washington in pursuit of US strategic interests in the region.

Fighting raged for a fourth straight day Friday, with US helicopters firing Hellfire missiles into Sadr City, a vast and impoverished area of Baghdad that is home to some 2 million people. US military sources said the attack killed four “terrorists.” Film from the area, however, showed dead and wounded children and there were reports that attacks caused dozens of civilian casualties.

The night before, US and British fighter planes bombed neighborhoods in Basra, the port city in southern Iraq, with a population of 1.5 million.

The US military reported Friday morning that American troops had fought running battles with Iraqi militiamen across six neighborhoods of Baghdad the day before. The Pentagon claimed that US forces killed 42 people in the fighting in the Iraqi capital, labeling all of the dead as “terrorists.”

According to some Iraqi estimates, the dead in Basra alone now number over 400, with hundreds more wounded. Fighting is also raging across much of Iraq, with fierce battles reported in Kut, Hilla, Amara, Kirkuk, and Baquba. US sources put the death toll Friday at 170.

American occupation forces have clearly stepped up their role in the crackdown, as Iraqi puppet forces have failed to achieve their objectives. In Basra, some 30,000 Iraqi troops and police have apparently been unable to wrest control from the Mahdi Army over at least three quarters of the city.

While Maliki had initially given a 72-hour ultimatum for the Sadrists in Basra to lay down their arms, he extended it Friday until April 8. The date coincides with scheduled testimony by Gen. David Petraeus, the US military commander in Iraq, and US Ambassador Ryan Crocker to Congress on proposals for continued troop deployments in the occupied country. The eruption of fighting has already led to speculation that Petraeus and the administration may well call for a suspension of the withdrawals that were to have reduced US forces to 140,000—still above the “pre-surge” levels—by this summer.

In Baghdad, meanwhile, the Washington Post reported: “US forces in armored vehicles battled Mahdi Army fighters Thursday in Sadr City, the vast Shiite stronghold in eastern Baghdad, as an offensive to quell party-backed militias entered its third day. Iraqi army and police units appeared to be largely holding to the outskirts of the area as American troops took the lead in the fighting. “Four US Stryker armored vehicles were seen in Sadr City by a Washington Post correspondent, one of them engaging Mahdi Army militiamen with heavy fire. The din of American weapons, along with the Mahdi Army’s AK-47s and rocket-propelled grenades, was heard through much of the day. US helicopters and drones buzzed overhead.”

Baghdad, like Basra before it, has been placed under a 24-hour curfew that began Thursday night and will run at least until Sunday morning. The effect is to turn the city’s streets into a free-fire zone for occupation troops and their Iraqi puppet allies.

Speaking at the White House Friday, President George W. Bush called the bloody clashes a “defining moment in the history of a free Iraq” that demonstrated the Iraqi regime’s commitment to “even-handed justice” and Maliki’s “leadership.”

The American president added: “There’s going to be violence. And that’s sad. But this situation needed to be dealt with, and it’s now being dealt with — just like we’re dealing with the situation up in Mosul.”

Referring to Maliki, Bush declared: “This was his decision. It was his military planning. It was his causing the troops to go from point A to point B. And it’s exactly what a lot of folks here in America were wondering whether or not Iraq would even be able to do in the first place.”

There is no reason to believe the official story coming out of the White House and the Pentagon that the sieges being laid to Basra and Sadr City are the result of some independent decision made by the Maliki regime. Whatever differences may exist over the timing or execution of this operation, it has clearly been carried out to fulfill definite US objectives.

The operation comes barely one week after Vice President Dick Cheney’s surprise visit to Baghdad for talks that centered on provincial elections scheduled for October, the future of Iraq’s oil industry and plans for the continued and long-term occupation of Iraq by US forces.

The bloodbath that is now being carried out is in all likelihood the practical outcome of these discussions.

While claiming that Maliki is upholding the rule of law against “gangs, militias and outlaws,” Washington has deliberately instigated what amounts to a civil war between rival political factions and militias within Iraq’s majority Shia population in order to advance its own predatory interests in the country.

The crackdown has not been launched against militias in general, but at Sadr’s Mahdi Army. Its aim is to severely weaken the Sadrists to the benefit of their political rivals, Maliki’s Dawa party and its principal government ally, the Islamic Supreme Council of Iraq (ISCI), led by Shia cleric Abdul Aziz al-Hakim, whose own militia, the Badr Brigade, is well represented in the government’s security forces.

In an analysis prepared last November, the International Crisis Group described the conflict between the Shia factions as taking “the form of a class struggle between the Shiite merchant elite of Baghdad and the holy cities, represented by ISCI (as well, religiously, by [Grand Ayatollah] Sistani), and the Shiite urban underclass,” which is the principal base of support for the movement led by Sadr.

The determination to suppress the Sadrist movement is driven in part by the electoral calendar. Those now holding power in the Maliki government—who have little in the way of mass support—fear that the Sadrists could sweep provincial elections set for October.

It is worth recalling that the last major urban siege conducted in Iraq—the razing of the predominantly Sunni city of Fallujah in November of 2004 in which thousands of Iraqi civilians died—was also carried out in preparation for US-organized elections scheduled three months later.

The US interest in this conflict is clear. While the Sadrists have repeatedly demanded the withdrawal of US forces, Maliki’s Dawa Party and the ISCI have made clear that they are prepared to support an indefinite occupation.

While the ISCI supports the carving out of an autonomous Shia region in the south in order to lay hold of the region’s oil wealth—it includes 60 percent of the country’s known reserves—the Sadrists have rejected regionalism in favor of a centralized federal government. To realize their objectives, the ISCI must oust the Sadrists and other rivals from positions of control in Basra and elsewhere.

As the Wall Street Journal reported Friday, “The battle for Basra marks the latest clash over the region’s biggest source of wealth: its oil reserves, comprising 9.5% of the world’s total.”

The Journal reported that during his recent visit, Cheney “held one-on-one meetings with Sunni, Shiite and Kurdish leaders in Iraq to speed passage of a law opening Iraq’s enormous petroleum reserves to more efficient production by global oil companies.”

While the passage of a national law opening Iraq’s oil wealth to foreign exploitation has been held up, the Journal noted, “Kurdish officials in Iraq’s semi-autonomous northern enclave have passed an oil law of their own and are signing deals with foreign firms without waiting for permission from Baghdad.”

Washington may well be seeking to forge similar relations in the south of Iraq, with even larger oil reserves, and would certainly be prepared to spill considerable amounts of blood to secure such a prize.

Those who point to the eruption of violence in Iraq as a manifestation of the “failure of the surge” are missing the point. The Bush administration has deliberately provoked this violence in pursuit of the objective that has driven the Iraq intervention from its outset: the cementing of semi-colonial US control over the country and its oil wealth.

US actions have compelled the Sadrist movement to renounce, at least in practice, the cease-fire that it initiated last August. This began not just with this week’s military offensive, but with a prolonged campaign by US occupation forces, the Maliki government and the Badr Brigade to use the cease-fire as a cover for arresting and killing thousands of Sadrists. It is this campaign that produced the so-called “rogue” elements that have fought back, providing a pretext for intensifying the repression.

These actions, however, have only underscored the failure of five years of American occupation to either install a reliable puppet regime or quell the resistance of the Iraqi people. The US military’s sealing off of Sadr City, the air and ground attacks against the Mahdi Army militia and the imposition of the round-the-clock curfew have all failed to halt the mortar and rocket attacks on the heavily fortified Green Zone, which was hit more than 20 times on Friday, with the US Embassy compound, the United Nations offices and the offices an Iraqi vice president all suffering direct hits.

The principal result of the US strategy is the unleashing of barbarism against millions of people living in two major cities—Baghdad and Basra.

Residents of Basra told the BBC Friday that the level of violence being inflicted on the city is the worst in memory, surpassing even that of the repression carried out by the Iraqi military against the 1991 Shia uprising that followed Iraq’s defeat in the first Persian Gulf War. It should be recalled that one of the pretexts incessantly repeated by the Bush administration for its 2003 invasion was that Saddam Hussein had “killed his own people.” But now, with ample backing from the US military, Washington’s Iraqi puppet Maliki is doing the same thing.

Aside from those killed and wounded, the entire population has been locked in their homes under conditions of rising early summer heat and dwindling water and food supplies. Both electricity and water supplies have been cut off to Basra.

“This is a catastrophe that could lead to a huge problem as we are entering summer and, of course, if it continues like this, it will lead to waterborne diseases including diarrhea,” Mahdi al-Tamimi, head of the Basra’s Human Rights Office told the United Nations news agency, IRIN. “All aspects of life have been paralyzed with the closure of schools, government offices and markets due to clashes that have forced people indoors with not enough food as there was no prior notice for this operation.”

“The humanitarian situation is getting worse by the minute — not the hour or the day — due to clashes taking place in the streets; as a result, the humanitarian effort has been severely hampered and paralyzed,” Salih Hmoud, head of the Iraqi Red Crescent Society’s office in Basra, told IRIN on Thursday.

Lack of clean water has led to outbreaks of diarrhea in Basra. “Some of these people with diarrhea have somehow managed to defy the curfew and reach nearby hospitals on foot but the majority is still in their houses,” said Hmoud. “This is very dangerous because they can die if they are not treated.”

Reporting on Baghdad, Patrick Cockburn of the British Independent noted that Sadr City’s two million residents have been encircled by the US military and ordered to stay indoors. He quoted a Sadr City resident named Mohammed, who said, “We are trapped in our homes with no water or electricity since yesterday. We can’t bathe our children or wash our clothes.” Temperatures in both Baghdad and Basra have risen into the upper 90s (30s Celsius).

Both Maliki (who has vowed to “fight until the end”) and US military sources have indicated that the sieges being waged against Basra and Sadr City have only just begun. The strategy of “clearing” the crowded slum neighborhoods will take many more days if not weeks of combat. It threatens a bloodbath that could easily eclipse the one that was inflicted upon Fallujah more than three years ago.