Ukrainian President Volodymyr Zelensky held a 30-minute telephone conversation with US President Joe Biden. 

The news was announced by Zelensky on Twitter, where he said they discussed anti-Russian sanctions and defense support for Ukraine. 

"We must stop the aggressor as soon as possible," he said. 

Ukrainian President Volodymyr Zelenskiy has set his terms for further negotiations with Russia, insisting that Russian forces must "stop bombing people" before talks on a ceasefire can begin. 

Speaking in an interview with CNN and Reuters, Zelenskiy said: "It is necessary to at least stop bombing people, just stop bombing and then sit down at the negotiating table." 

Zelenskiy urged NATO members to establish a no-fly zone to stop the Russian air force.