Biden expressed his determination in a letter to Congress and a rare call to a television program, starting a crucial week that includes a NATO summit in Washington, where he will face increased scrutiny. "I am firmly committed to staying in the race," Biden wrote. "It is time to come together, move forward as a unified party, and defeat Donald Trump. It's time for it to end."

He followed up by calling MSNBC's "Morning Joe" program, stating his frustration with the party's elites. "Any of these guys that don't think I should run—run against me. Announce for president, challenge me at the convention," he said.

Trump, unusually quiet since the debate, spoke out on Fox News, predicting Biden would resist pressure to withdraw. "He's got an ego and he doesn't want to quit," Trump said in an interview with Sean Hannity.

Despite Biden's determination, the pressure on him, as the oldest president in US history, continued to grow. Congressman Adam Smith, the senior Democrat on the US House Armed Services Committee, became the sixth Democratic lawmaker to publicly suggest Biden should step aside. "I think it's become clear he's not the best person to carry the Democratic message," Smith told CNN.

Nevertheless, other senior Democrats voiced their support for Biden. "I made clear that day after the debate publicly that I support President Joe Biden and the Democratic ticket. My position has not changed," House Minority Leader Hakeem Jeffries told CNN.

Biden expressed his determination in a letter to Congress and a rare call to a television program, starting a crucial week that includes a NATO summit in Washington, where he will face increased scrutiny. "I am firmly committed to staying in the race," Biden wrote. "It is time to come together, move forward as a unified party, and defeat Donald Trump. It's time for it to end."

He followed up by calling MSNBC's "Morning Joe" program, stating his frustration with the party's elites. "Any of these guys that don't think I should run—run against me. Announce for president, challenge me at the convention," he said.

Trump, unusually quiet since the debate, spoke out on Fox News, predicting Biden would resist pressure to withdraw. "He's got an ego and he doesn't want to quit," Trump said in an interview with Sean Hannity.

Despite Biden's determination, the pressure on him, as the oldest president in US history, continued to grow. Congressman Adam Smith, the senior Democrat on the US House Armed Services Committee, became the sixth Democratic lawmaker to publicly suggest Biden should step aside. "I think it's become clear he's not the best person to carry the Democratic message," Smith told CNN.

Nevertheless, other senior Democrats voiced their support for Biden. "I made clear that day after the debate publicly that I support President Joe Biden and the Democratic ticket. My position has not changed," House Minority Leader Hakeem Jeffries told CNN.