US President Joe Biden made an impassioned appeal to Russian President Vladimir Putin to step back from war with Ukraine on Tuesday, speaking starkly of the "needless death and destruction" Moscow could cause and international outrage Putin would face.

In a nationally televised speech, Biden said the United States estimates that 150,000 Russian troops now encircle Ukraine, a higher number than previous estimates of about 100,000. He said reports that some forces had withdrawn were welcome, but they were unverified and an invasion remained very much a possibility.

Biden said diplomacy remains...