Despite overwhelming difficulties, Ukraine is applying constant pressure to Russia's front line, Petraeus said, and the cracks may yet show.

 The US gave Ukraine a shot at fire superiority with cluster munitions, "but now we have to give them the chance to win it," Dan Rice told Insider.

Some security officials and Soviet experts have said they believe Putin likely ordered the assassination out of revenge for Prigozhin's failed mutiny.

Despite overwhelming difficulties, Ukraine is applying constant pressure to Russia's front line, Petraeus said, and the cracks may yet show.Confusion around Prigozhin's apparent death highlight the challenges of getting the truth about events in Russia"He was good at holding a gun and screaming curse words into the TV camera but not so much at actually leading men in combat," a Russia expert said.Here are three possible explanations of what happened to Yevgeny Prigozhin based on what we know so far.

Russian President Vladimir Putin on Thursday called Wagner Group boss Yevgeny Prigozhin a "talented man" after his suspected death in a plane crash.Yevgeny Prigozhin was presumed dead on Wednesday after a Wagner-affiliated plane plummeted to theground outside of Moscow.Telegram channels linked to the Wagner leadership were furious after Yevgeny Prigozhin's apparent death in a plane crash near Moscow.Wagner Group boss Yevgeny Prigozhin is presumed dead after a plane crash. The 'troll factory' boss was falsely reported dead after a 2019 crash.

Kyiv's military intelligence agency said its forces left Crimea without suffering any casualties and published a video of troops hoisting the flag.Wagner Group boss Yevgeny Prigozhin is presumed dead after a plane crash in Russia. Some warned he could face Putin's revenge after his uprising.John Sawers, who used to head up the UK's intelligence service, suggested a bomb could have brought downYevgeny Prigozhin's plane.