text:  Hello, I'm Moira Alderson with the BBC News. Worries about Joe Biden's age and mental acuity are continuing to swirl after he made two high-profile gaffes at his first unscripted news conference for eight months. The US president accidentally introduced the Ukrainian leader, Volodymyr Zelensky, as President Putin. He also called his deputy, Kamala Harris, Vice President Trump. Jared Hill from CBS News says there's continuing uncertainty among Democrats in the US Congress.