The House Minority leader in the US Congress, Hakeem Jeffries, met on Thursday with President Joe Biden about mounting concerns over his reelection bid in the November's election. He told his colleagues in a letter on Friday that he shared with Biden the "insight" and "conclusions" voiced by fellow Democrats.

It is not clear whether Jeffries gave his own opinion about what Biden should do or how the president responded. More than a dozen Democrats, mostly House lawmakers, have publicly called for him to step aside.

A growing number of donors are adding to the pressure, with some saying they will withhold their funds.

US media reports say Biden's campaign team is conducting its own poll to see if Vice President Kamala Harris would have a better chance against Trump.

Other polls show a close race. One conducted by ABC News found her support rate at 49 percent, compared to 47 percent for Trump. However, most others show the former president in the lead.