NEW YORK, June 28. /TASS/. White House is losing confidence that Ukraine will ever take back the land now controlled by Russian troops, CNN reported on Tuesday, citing US officials.

Advisers to President Joe Biden have begun debating how and whether Ukrainian President Vladimir Zelensky should shift his definition of a "victory" and agree to the possibility that his country has shrunk, CNN reported.

This pessimistic assessment does not mean the US will pressure Ukraine into making formal territorial concessions, the officials emphasized to CNN.

However not everyone in the administration is that worried, according to CNN. National security adviser Jake Sullivan has remained highly engaged with his Ukrainian counterparts and "spent hours on the phone" last week discussing Ukraine’s efforts to recapture territory with the country’s defense chief, Valery Zaluzhny, officials familiar with the call told CNN.

"Whether Ukraine can take back these territories is in large part, if not entirely, a function of how much support we give them," a congressional aide told CNN. He added that Ukraine has asked the US for at least 48 multiple launch rocket systems, but the Pentagon has only promised eight to date.