At least three US soldiers were killed and several others wounded in a suicide bombing in northern Afghanistan as US and Afghan officials continued talks on a permanent American military presence after 2014.

The bomb blast took place shortly before noon on Wednesday in a park in Maimanah, the capital of Afghanistan’s northern Faryab province. AP video showed a horrific scene, with pavements splattered, blood and body parts strewn around, and badly wounded American soldiers waiting for assistance.

In addition to the three US soldiers, at least four Afghan policemen were killed and several more American soldiers and Afghan police were among the more than 20 wounded in the attack. Most of the wounded were reported in critical condition.

According to some accounts, the US soldiers were targeted after they left their base to explore the town’s municipal park. Other reports, however, indicated that the bomber’s target was a meeting of Afghan officials taking place nearby.

The Taliban claimed credit for the attack and quoted residents as saying that after the bombing US soldiers opened fire on civilians, killing one and wounding several.

Reuters quoted Faryab’s provincial police chief, Abdul Khaliq Aqsai, as saying that the American soldiers were taking photographs in the park when they were attacked. “We warned them not to roam around the city,” Aqsai told the news agency.

The police chief said witnesses reported that the bomber walked right up to the troops, shouted “Allahu Akbar” (God is greatest) and detonated his explosives.

Faryab, over 80 percent of whose population is made up of Turkmen and Tajiks, has been among the least affected by the armed resistance to the decade-old American-led occupation of Afghanistan, with Norwegian troops taking the principal responsibility for security in the province.

The bombing was only the latest in a series of attacks that have given the lie to Pentagon claims about a steadily improving security situation created by the Obama administration’s “surge,” which raised American troop levels to over 100,000. On Tuesday, it was reported that three foreign troops were killed in attacks, two by roadside bombs in the south and east of the country and a third in an attack by resistance forces in the east.

At least 60 American troops have been killed since the beginning of the year. Of those, at least seven died in what NATO refers to as “green-on-blue” killings, meaning the gunning down of occupation troops by members of the Afghan puppet forces that are supposedly their allies. In total, 17 US and other NATO troops have been killed in this fashion since the start of the year.

Several of these attacks have been attributed to the popular outrage that has seeped into the US-trained security forces over a series of outrages committed by occupation forces. These have included the release of a video in January showing laughing US Marines urinating on Afghan corpses, the burning of copies of the Koran at the US Bagram Air Base, and last month’s horrific massacre of 17 Afghan civilians, allegedly by one US soldier, Staff Sgt. Robert Bales.

The US-NATO command in Kabul this week acknowledged that security failures in the training and vetting of Afghan troops and police had contributed to the death toll.

“Although the incidents are small in number, we are aware of the gravity they have as an effect on morale,” ISAF spokesman Brigadier-General Carsten Jacobson told the media. “Every single incident has an out-of-proportion effect on morale, and that goes for coalition forces as it goes for Afghan national security forces.”

Indeed, the killings have shaken confidence in the US-NATO strategy of drawing down foreign occupation forces and transferring responsibility for security to the Afghan puppet forces. The US-NATO command has been forced to assign soldiers to guard occupation troops from their ostensible allies around the clock, including while they sleep.

These types of attacks have also spread to the Afghan security forces themselves. Last Friday, nine members of the Afghan Local Police were shot and killed by one of their colleagues, reportedly a Taliban infiltrator, in the Yayakhil district of eastern Afghanistan’s Paktika province. The infiltrator drugged the police, shot them as they slept and disappeared with a truck and the units’ weapons.

The incident took place within a unit of the Afghan Local Police, a militia-style force that the US military is setting up throughout the country to combat Afghan resistance elements. Afghan human rights advocates have charged that this new paramilitary force, often under the command of local warlords, has been responsible for extra-judicial killings and other abuses. Nonetheless, the Pentagon plans to triple its size, from 10,000 to 30,000, over the next two years.

A similar incident was reported on Wednesday in which a police officer in the Chardara district of Kunduz province turned his gun on the local police chief and his two bodyguards, killing them all and then fleeing.

Amid this escalating violence, Washington is pushing aggressively to conclude negotiations with the US-backed regime of President Hamid Karzai on a “strategic partnership” agreement that would allow the US to keep troops and maintain bases inside Afghanistan long after 2014, the formal deadline set by NATO for the withdrawal of all foreign combat forces from the country.

News agencies quoted unnamed Pentagon officials Wednesday as saying that the two sides were close to an agreement on a memorandum of understanding regarding the night raids carried out by US special operations troops in Afghanistan. Karzai had demanded a halt to these raids, in which heavily armed American troops force their way into Afghan homes in the middle of the night in search of suspected supporters of the armed opposition groups. The practice has aroused intense hatred among the Afghan people, both because of the large number of raids that have resulted in civilian deaths and the humiliation to which Afghan families are subjected.

US military officials made it clear from the outset that they were not about to submit to the orders of Karzai, whom they regard as an unreliable puppet, and would continue with the raids, which they consider an essential tactic in suppressing resistance to occupation.

According to media reports, under the deal being negotiated the raids would go on with a fig leaf of Afghan legitimization, including some type of judicial warrants and greater involvement by Afghan troops. Washington’s aim is to put the issue to rest so that it can push through the strategic partnership deal before a NATO summit that is scheduled to convene in Chicago on May 20.

Speaking in Norfolk, Virginia on Tuesday, Secretary of State Hillary Clinton said of the deal, “We anticipate that a small number of forces will remain, at the invitation of the Afghan government, for the sole purpose of training, advising, and assisting Afghan forces and continuing to pursue counterterrorism operations.”

She claimed that Washington was not seeking “permanent American military bases in Afghanistan or a presence that is considered a threat to the neighbors.”

The type of continuing operations outlined by Clinton would likely involve tens of thousands of US troops. And while Washington may not wish to call the bases that they will occupy “permanent,” Pentagon officials foresee a military presence in the country for decades to come.

As for “the neighbors,” Iran, Russia, China and Pakistan have all expressed opposition to a continued US military presence in Afghanistan, seeing it as an attempt by US imperialism to militarily exert its hegemony over the strategic and energy-rich region.

Hamid Karzai’s spokesman, Aimal Faizi, told Reuters that the Afghan regime has demanded to know from US officials “how many bases will be there, how many soldiers and what will be their mission.” The news agency reported that US officials proposed that the question be dealt with separately while they push ahead toward signing the strategic partnership accord.