Washington, Mar 8 (AP) President Joe Biden's top intelligence official said Tuesday the U.S. believes Russia underestimated the strength of Ukraine's resistance before launching an invasion that has likely caused thousands of Russian casualties.

Director of National Intelligence Avril Haines told a congressional panel that U.S. officials believe Russian President Vladimir Putin feels “aggrieved” by Russia's failure to subdue Ukraine and that he perceives that he cannot afford to lose the war. But what Putin might consider a victory could change given the escalating costs of the conflict to Russia, Haines said.

Also Read | Joe Biden to Ban Russian Oil Imports Over Ukraine War, Says Source.

Despite Putin's announcement that he would raise Russia's alert level for nuclear weapons, Haines said the U.S. has not observed unusual changes in Russia's nuclear force posture.

Haines said it is “unclear at this stage” whether Russia will try to conquer all of Ukraine, something that would require more resources than Putin has committed. (AP)

Also Read | Operation Ganga: India Starts Evacuation of Its Citizens from Ukraine’s Sumy to Poltava.

(The above story is verified and authored by Press Trust of India (PTI) staff. PTI, India’s premier news agency, employs more than 400 journalists and 500 stringers to cover almost every district and small town in India.. The views appearing in the above post do not reflect the opinions of LatestLY)