After the sinking last week of the Moskva, the flagship of Russia’s Black Sea fleet, and a major expansion of NATO arms shipment to Ukraine, the imperialist proxy war against Russia in Ukraine is escalating further, with Ukrainian President Zelensky now threatening an “end of all negotiations” with Russia.

The exact circumstances of the sinking of the Moskva remain unclear. While Kiev is claiming that it fired two Neptune missiles that hit the ship—a claim supported by the US—the Kremlin is insisting that an explosion on board and “stormy seas” accounted for its sinking. Whatever the truth, however, the loss of the Moskva is universally regarded as a massive military humiliation and setback for Russia. It is the most significant loss any navy has experienced in decades and has been compared to the catastrophe suffered by the Russian navy in the war with Japan in 1904-05.

Motivated no doubt by the attempt to offset the catastrophic impression left by the sinking of the Moskva, and in response to the endless provocations by the imperialist powers, which have funneled weapons worth billions of dollars to the Ukrainian army, Russia has escalated air strikes on targets across Ukraine, and has made a concerted effort to seize Mariupol.

As of Sunday, Russian forces had reportedly destroyed an ammunition factory near Kiev and seized large parts of the southeastern city of Mariupol with the exception of territory around the Azovstal factory. According to Russian Major General Igor Konashenkov, 2,500 fighters affiliated with the neo-Nazi Azov Battalion were still holding out at the Azovstal factory, including 400 foreign mercenaries who had been recruited mostly from Europe and Canada.

Kiev rejected an ultimatum issued by the Russian army to the remaining Ukrainian forces to surrender by noon on Sunday. Ukraine’s prime minister has insisted that the troops will “fight until the end.”

In response to threats by Russian officials that forces still fighting in Mariupol would be “eliminated,” President Zelensky warned that the destruction of “our guys will put an end to all negotiations with Russia.”

Mariupol has been under siege for seven weeks. A humanitarian catastrophe has been unfolding among the 100,000 civilians who have remained in the city and have reportedly experienced serious shortages of electricity, water and food. Negotiations between Russia and Ukraine about the establishment of corridors to evacuate the civilian population, including from Mariupol, have repeatedly ended in failure.

With a pre-war population of 400,000, Mariupol is the second largest city in East Ukraine, the so-called Donbass, and is of key strategic and economic significance. It is located on the northeastern cost of the Sea of Azov and, up until the war, much of Ukraine’s imports and exports went through its ports.

If taken by Russia, the city would form a critical part of a land bridge between the Crimean Peninsula in the Black Sea and the other territories controlled by Russia in the Donbass, around Donetsk and Lugansk. Such a scenario would be a major military setback for Ukraine and create significant economic and logistical challenges for the Zelensky government in the continuation of the war.

It is widely acknowledged that the Azov Battalion, which includes hardcore neo-Nazis who admire Adolf Hitler and are dreaming of a worldwide battle for the supremacy of the “white race,” has played the central role in the battle of Mariupol since the beginning of the war this year. In the civil war that erupted after the US-backed February 2014 coup in Kiev, a bloody battle between far-right militias such as the Right Sector and the Azov Battalion and pro-Russian separatists ended with the city falling to the Kiev regime. Later that year, the Azov Battalion was integrated into Ukraine’s National Guard and set up its official headquarters in Mariupol.

In an interview with local media, Zelensky has indicated that the Azov fighters have effectively been given carte blanche by the government. He said, “‘the Azovtsy’ are already heroes and no one would forbid them to take certain measures.” Zelensky has awarded commanders of the Azov Battalion orders of “heroes of Ukraine,” and his government has encouraged a recruitment campaign by Azov aimed at attracting far-right forces from all over the world to fight in the war.

In an interview with CNN’s Jake Tapper, sitting in front of the Ukrainian national flag and a flag with the emblem of the Nazi collaborationist Organization of Ukrainian Nationalists (OUN), Zelensky acknowledged that “all of the world, all of the countries have to be worried” that Russia might use nuclear weapons.

However, far from advocating a de-escalation of the conflict, he echoed the provocative rhetoric of US President Joe Biden, who alleged last week that Russia was perpetrating “genocide” against Ukrainians, and demanded “stronger, more destructive weapons” for Ukraine and a complete embargo on Russian oil and gas. He also warned that Ukraine would not surrender the eastern part of the country, with Russia reportedly preparing a major offensive in the Donbass, set to begin in the coming days.

Ukraine is already packed with advanced NATO weapons that have played a central role in the war. The advanced weapons systems at the disposal of Ukraine’s army and far-right forces in no small measure account for what are devastating losses by the Russian army, numbering in the thousands of soldiers and including dozens of high-ranking military officials.

Just since the beginning of the war on February 24, the US has committed to $2.6 billion in weapons deliveries to Ukraine, including tanks, anti-tank missiles and other advanced weapons systems. The US has also significantly expanded its cooperation with Ukraine’s army on “intelligence operations.”

Even before the war, the US and NATO spent billions on arming Ukraine’s military, while the CIA, according to Yahoo News, ran “a secret intensive training program in the U.S. for elite Ukrainian special operations forces and other intelligence personnel” to prepare an “insurgency” against Russia.

Now, the US military is using the experience of the imperialist proxy war in Ukraine to prepare systematically for a direct military confrontation with Russia and China, i.e., for world war. A report by the Associated Press noted that “U.S. Army trainers are already using lessons learned from Russia’s war against Ukraine as they prepare soldiers for future fights against a major adversary such as Russia or China.”

Army Secretary Christine Wortmuth told the AP, “I think right now the whole Army is really looking at what’s happening in Ukraine and trying to learn lessons.” These “lessons,” she said, ranged from equipment and logistics problems facing the Russian army to the kind of tanks the US should be prepared to deploy to the muddy terrain prevailing in Europe.

With barely veiled enthusiasm about the unfolding war, Wortmuth stated, “The Russia-Ukraine experience is a very powerful illustration for our Army of how important the information domain is going to be. We’ve been talking about that for about five years. But really seeing it and seeing the way Zelenskyy has been incredibly powerful... This is a world war that the actual world can see and watch in real time.”