Warsaw, Mar 27 (IANS): US President Joe Biden's call for Vladimir Putin to be "removed" from power is setting off alarm bells among US foreign policy experts, who fear that it could escalate tensions even after the Kremlin scales back its war aims in Ukraine, Daily Mail reported.

"For God's sake this man cannot remain in power," Biden had said in a shocking apparent call for regime change in Moscow at the end of a impassioned speech from Poland.

The "unscripted" remark, which the White House scrambled to walk back as the Kremlin expressed fury, came at the end of an otherwise resolute and fiery speech rallying the free world to unite in opposition to "autocracy" and support of Ukraine.

Richard Haass, the Council on Foreign Relations president, tweeted his concerns that Biden had "just expanded US war aims, calling for regime change."

"However desirable it may be, it is not within our power to accomplish-plus runs risk it will increase Putin's inclination to see this as a fight to the finish, raising odds he will reject compromise, escalate, or both," wrote Haass, Daily Mail reported.

"Our interests are to end the war on terms Ukraine can accept & to discourage Russian escalation. Today's call for regime change is inconsistent with these ends," he added.

"The fact that it was so off-script in some ways makes it worse," because it could be read as Biden's genuine belief as opposed to his scripted words, Haas said.

Biden's remark could also diminish Putin's interest in compromise and increase his temptation to escalate in Ukraine, "because if he believes he has everything to lose then he'll believe he has nothing to lose," Haass said.