U.S. President Joe Biden had a private, emotional meeting with the widow and daughter of Alexei Navalny in California on Thursday, as his administration announced fresh sanctions against Russia over the death of the Kremlin opposition leader.

The visit at a hotel in San Francisco came as the White House backed Navalny's mother in her fight to retrieve his body, which Russian authorities have refused to release days after he died in an Arctic prison.

Navalny's team says the 47-year-old — the most outspoken critic of President Vladimir Putin — was murdered.