Russia warns of 'uncontrolled escalation' in Ukraine

STORY: Under pressure in the south of Ukraine, Russia fired missiles and drones into Ukrainian-held Mykolaiv on Sunday, destroying an apartment block in the ship-building city near the front and said the war was trending towards "uncontrolled escalation."

A Russian missile strike on Sunday wiped out the top floor of an apartment block in the city, sending shrapnel and debris flying, smashing windows and cracking walls, and leaving cars crushed under rubble.

Russian Defense Minister Sergei Shoigu said - without evidence - that Ukraine could escalate by using a "dirty bomb" - conventional explosives laced with radioactive material. Ukraine does not have nuclear weapons, while Russia has threatened to use its nuclear arsenal.

Ukrainian President Volodymyr Zelenskiy said Sunday that only Russia was capable of using nuclear weapons in the area, and that Russia's accusations are a signal of their own plans.

In a flurry of calls, Shoigu discussed what he called a "rapidly deteriorating situation" with French, British and Turkish counterparts, his ministry said, and also spoke with U.S. Defense Secretary Lloyd Austin for the second time in three days.

The White House National Security Council said in a statement it rejected Shoigu's false allegations that Ukraine is preparing to use a dirty bomb on its own territory, and that "the world would see through any attempt to use this allegation as a pretext for escalation."

Ukraine's advances in recent weeks around Kherson have been met with intensifying Russian missile and drone attacks on civilian infrastructure, which have destroyed about 40% of Ukraine's power system ahead of winter.

Russian occupation authorities are evacuating civilians deeper into Russian-held territory before an expected battle for Kherson -- a gateway to Crimea, which Russia annexed in 2014.