Ukraine war live updates: Moscow and Kyiv face off over downed POW plane amid suspicion and allegations

This is CNBC's live blog tracking developments on the war in Ukraine. See below for the latest updates. 

Question marks and suspicions surround the shooting down Wednesday of a Russian military transport plane that was carrying 65 Ukrainian prisoners of war and nine Russians.

Russia blamed Ukraine for the plane crash, saying it had used Western missiles to shoot the military transport Ilyushin-76 plane down over the border region of Belgorod, killing all on board, while the aircraft was en route to a prisoner exchange.

Ukrainian President Volodymyr Zelenskyy said Kyiv will fully investigate the circumstances around the crash, adding that "facts" were a key priority. He accused Russia of "playing with the lives of Ukrainian prisoners, with the feelings of their relatives and with the emotions of our society."

Kyiv was initially silent as details of the plane crash emerged Wednesday morning. Later, Ukraine's intelligence agency confirmed that a prisoner exchange had been scheduled but did not take place.

It said that it did not have "reliable and comprehensive information about who exactly was on board the plane and how many of them."

The "Ukrainian side was not informed about the need to ensure the safety of the airspace in the area of the city of Belgorod in a certain period of time, as was repeatedly done in the past," the agency added.

Separately, Ukraine's armed forces said in a statement they would continue to "control the airspace to destroy the terrorist threat" of strikes crossing the border from Belgorod into Ukraine's Kharkiv region.

Both black boxes have been retrieved from the Russian Ilyushin-76 military transport aircraft that was shot down Wednesday, a Russian state-run news agency said Thursday.

The two