The unprecedented challenge to Russian President Vladimir Putin by Wagner fighters has exposed fresh "cracks" in the strength of his leadership that may take weeks or months to play out, US Secretary of State Antony Blinken said on Sunday.

Blinken and members of the US Congress said in a series of television interviews that Saturday's turmoil in Russia has weakened Putin in ways that could aid Ukraine's counteroffensive against Russian forces within its territory while benefiting Russia's neighbors, including Poland and the Baltic states.

"I don't think we've seen the final act," Blinken said on ABC's "This Week" program after an aborted mutiny by forces led by Yevgeny Prigozhin.

Blinken said tensions that sparked the action had been growing for months and added the threat of internal turmoil could affect Moscow's military capabilities in Ukraine.

"We've seen more cracks emerge in the Russian facade. It is too soon to tell exactly where they go, and when they get there. But certainly, we have all sorts of new questions that Putin is going to have to address in the weeks and months ahead," Blinken told NBC's "Meet the Press" program.

Blinken described the turmoil as an "internal matter" for Putin.

"Our focus is resolutely and relentlessly on Ukraine, making sure that it has what it needs to defend itself and to take back territory that Russia seized," Blinken said.

US officials expect to learn more soon about the events that unfolded in Russia, including details of the deal with Prigozhin mediated by Belarusian President Alexander Lukashenko that led Wagner fighters to return to their bases.

"It may be that Putin didn't want to debase himself to the level of negotiating directly with Prigozhin," Blinken said.

'DISTRACTED AND DIVIDED'

Forces led by Prigozhin, a former Putin ally and ex-convict, have fought the bloodiest of battles in Russia's 16-month war in Ukraine.

"To the extent that the Russians are distracted and divided it may make their prosecution of aggression against Ukraine more difficult," Blinken told ABC.

House of Representatives Intelligence Committee Chairman Mike Turner said Putin's future actions in Ukraine could be inhibited by Prigozhin's assertion that the rationale for invading Ukraine was based on lies.

"Taking down the very premise makes it much more difficult for Putin to continue to turn to the Russian people and say, we should continue to send people to die," Turner told CBS' "Face the Nation" program.

Retired US Air Force General Philip Breedlove, former head of US European Command, said the turmoil demonstrates a degradation of Russian capabilities.

"One of the outcomes, I believe, of the last 36 hours, maybe 48 hours, is that the institutions that we have long seen as being very secure in Russia are slowly unraveling," Breedlove said in an interview. "The whole institution of the military now, the appearance of what the Russian military is, is much diminished."

US Senator Ben Cardin said the weekend turmoil in Russia does not ease Washington's need to continue aiding Ukraine as it launches its long-awaited counteroffensive against Russia.

"This is a critical time for Ukraine. This counteroffensive is going to be defining as to where we're going to be in the next year or two," Cardin, a Democrat who sits on the Senate Foreign Relations Committee, told Fox News.

Republican Representative Don Bacon, a former US Air Force general who sits on the House Armed Services Committee, told NBC that a diminished Putin would be a benefit for Russia's neighbors including Finland, Estonia, Latvia, Lithuania and Poland.

"It would be different if Putin was wanting to be a peaceful neighbor. But he's not," Bacon said.