WARSAW — President Biden said Russian President Vladimir Putin “cannot remain in power” in a forceful speech Saturday wrapping up a trip to Europe meant to bolster NATO’s response to Russia’s invasion of Ukraine.

 

The president’s remark initially seemed to suggest support for regime change — something the Biden administration has taken pains to avoid — though the White House later said Biden only meant Putin should not be allowed to exercise power over his neighbors or the region.

His words capped a fiery speech in which Biden also called Putin a “dictator,” warning him not to encroach on NATO territory and urging Ukrainians to steel themselves for a long battle. He framed the Kremlin’s invasion as the “test of all time” for democracy.

His trip came as fierce fighting continued in Ukraine. Officials in the western Ukrainian city of Lviv reported several powerful explosions on Saturday, and a large plume of smoke could be seen billowing in the air.