Putin's back against the wall in Ukraine - Biden

Us President Joe Biden says there are clear signs that Vladimir Putin is considering using chemical and biological weapons in Ukraine. He said Putin may consider this since his 'back is up against the wall'.

President Volodymr Zelensky has again appealed for direct talks with Mr Putin to try to end the fighting.

Meanwhile, Ukrainian cities remain under bombardment, with the city of Mariupol in greatest need.