American media are reporting that former US House Speaker Nancy Pelosi is signaling that Joe Biden should reconsider staying in the presidential race.

Pelosi, a longtime ally of President Biden, gave an interview with MSNBC on Wednesday, as Biden faces growing calls to step aside after his shaky performance in a televised debate against former President Donald Trump.

When asked whether she supports Biden, Pelosi said: "It's up to the president to decide if he is going to run. We're all encouraging him to make that decision, because time is running short."

Hollywood star George Clooney, a longtime Democrat who co-hosted a major fundraiser for Biden in June, called on the president to withdraw from the race.

Clooney wrote about the event in an article in The New York Times published on Wednesday, saying Biden was "the same man we all witnessed at the debate."

The actor said, "This is about age." He added, "We are not going to win in November with this president."

Biden gave a speech at a labor union meeting on Wednesday. He noted food prices and rents were too high, and said, "We have a whole range of things we're going to get done with your help in the second term."