Russian and Chinese warships will hold joint naval exercises in the Mediterranean Sea later this month, according to Chinese military sources. This unprecedented decision reveals the sharp tensions between the major world powers arising from the US-led “pivot to Asia” against China and the NATO war drive against Russia over the Ukraine crisis.

The exercises will mark the first time that Chinese warships carry out military operations in the Mediterranean. Chinese Defense Ministry spokesman Geng Yansheng said the Chinese navy would contribute warships currently on anti-piracy patrols off the coast of Somalia, in the Indian Ocean. The nine-ship Russo-Chinese fleet in the Mediterranean will practice refueling, escort and live-fire missions.

“The aim is to deepen both countries’ friendly and practical cooperation, and increase our navies’ ability to jointly deal with maritime security threats,” Geng said at a monthly briefing on Thursday.

Chinese officials implausibly downplayed any suggestion that the exercises were aimed at the United States and its European allies. “What needs saying is that these exercises are not aimed at any third party and have nothing to do with the regional situation,” Geng declared.

A glance at the “regional situation” shows, in fact, that military tensions are escalating between the NATO imperialist powers, Russia, and China—a situation for which NATO’s aggressive policies are mainly responsible. While NATO stages military drills aimed at Russia across Eastern Europe and the Black Sea, war is spreading in the Mediterranean. A US-led proxy war is burning in Syria, as is the civil war that erupted in Libya after the 2011 NATO war destroyed Colonel Muammar Gaddafi’s regime.

Russian and Chinese warships already had appeared in the Mediterranean during the Libyan and Syrian wars. Chinese vessels evacuated 30,000 Chinese workers from Libya during the 2011 war, while Russian warships patrolled the Syrian coast in 2013 to dissuade NATO from launching missile strikes on Syria, a Russian ally.

If Moscow and Beijing have taken the extraordinary step of organizing live-fire exercises off the coast of Europe, however, this is to send Washington and its European allies a political signal. US-led policies of strangling Russia’s economy with financial sanctions and seeking to topple Russian President Vladimir Putin, or isolating China through the US “pivot to Asia,” pose the threat of all-out war.

Chinese commentators indicated the Mediterranean exercises were also Chinese President Xi Jinping’s response to US-Japanese military deals in the Asia-Pacific, agreed between Obama and Japanese Prime Minister Shinzo Abe during Abe’s visit to Washington this week.

“Russia wants to show the United States it is not isolated and can launch exercises near Eastern Europe. And as a result of Abe’s visit to the United States and the upgraded Japan-American military relationship, Xi wants to show the United States he has good relations with Russia,” said Shi Yinhong, a professor of international relations at Renmin University in Beijing.

James Hardy, Asia-Pacific editor of IHS Jane’s Defense Weekly, said the exercises marked a new stage in the development of the Chinese navy’s fighting capabilities and would be seen as a challenge by ruling elites in the NATO countries.

“The geopolitical significance of its exercising along Russia will not be lost on the US and NATO, although it would be churlish of anyone in the West to complain about it, given the number of joint drills the US and its allies conduct in China’s near seas,” he told the New York Times .

The greatest danger facing the world’s population is that the risk of world war is largely hidden from the working class internationally. However, military standoffs such as the US threat to arm the far-right regime in Kiev against pro-Russian forces in east Ukraine, or the Japanese standoff with China over the Senkaku/Diaoyu islets, could erupt into all-out wars threatening the very survival of humanity.

In an interview in March, Putin confirmed that the Russian military prepared for possible nuclear war with NATO in the initial weeks of the conflict in Ukraine triggered by a NATO-backed, coup in Kiev last year.

The only progressive basis for struggle against the danger of world war is the political mobilization of the working class internationally against war. This struggle cannot be left to an alliance between the reactionary regimes in Moscow and Beijing.

Oscillating between maneuvers designed to warn off NATO policymakers and attempts to work out deals with them, the policies of the capitalist oligarchies that emerged from the restoration of capitalism in China and the USSR only deepen the danger of war. It is safe to predict that the imperialist powers will respond to this exercise by stepping up military pressure on Moscow and Beijing, and any other regime that they see as a potential obstacle to their interests.

Reckless imperialist policies are clearly pushing the Russian and Chinese towards a strategic alliance. Last year, Russia and China signed a $400 billion pipeline deal allowing Russia to export its oil and gas towards China, bypassing a cut-off of Russian energy exports to Europe, should this arise. At the same time, Moscow and Beijing held joint naval exercises off China’s Pacific coast. As US and European sanctions hit Russia and the Russian ruble plunged on the currency markets last December, top Chinese officials said Beijing would offer Russia financial backing.

Beijing is now offering symbolic support to Moscow in the Ukraine crisis, by preparing to send an official delegation to May 9 celebrations in Moscow of the Soviet victory over Nazi Germany in World War II. Officials from US, the leading European powers, and the NATO-backed Ukrainian regime have announced that they will boycott the ceremony.

A defensive Russo-Chinese alliance aimed at the US, Europe and Japan all too obviously draws potential battle lines of a Third World War. However, it is hardly clear that such a war could only emerge in the form of a conflict between unstable alliances of the imperialist powers, on the one hand, and Russia and China on the other.

Divergences are rapidly emerging between the major imperialist powers themselves over what policy to pursue towards Russia and China. In March, in a stunning rebuke to Washington, the European powers bucked US appeals not to join the Chinese-led Asian Infrastructure Investment Bank (AIIB). Several European governments are openly opposed to financial sanctions against Russia.

Moreover, the Sino-Russian relationship is itself deeply fraught. Powerful tensions exist between Beijing, flush with export revenues from cheap-labor Chinese export industries, and Moscow, which has never recovered from the industrial collapse that followed the restoration of capitalism in the USSR.

China’s Global Times newspaper pointed to the distrust between the rival capitalist cliques in Russia and China in an article discussing why Chinese financial aid would not suffice to overcome US-European economic sanctions.

It wrote, “Due to Russia’s large population of 140 million people, its modernity and strong currency cannot be solely supported by oil, gas and timber … China is capable of offering sufficient capital, technologies and markets to Russia, but these efforts can only take limited effect if Russia’s economy still relies heavily on oil exports and lacks structural diversity. If Chinese investment in Russia shoots up under these circumstances, Moscow might suspect China has ulterior motives. Russia does not want to be a vassal of the Chinese economy.”