Despite prospects for direct diplomatic talks on June 2 in Istanbul, Russia and Ukraine remain in a spat over the peace memorandums outlining prerequisites for ending the war to be discussed there. Russian FM Sergey Lavrov originally proposed the talks on Wednesday.

President signals impatience over Ukraine conflict, stalled peace efforts, according to the report quoting sources - Anadolu Ajansı

Donald Trump is reportedly considering new sanctions against Russia after President Vladimir Putin failed to follow up on a promised draft of peace terms and escalated airstrikes on Ukraine.

The White House did not immediately issue a readout on the Trump-Putin call, which was due to be followed by a conversation between the US president and Ukrainian President Volodymyr Zelensky.

On the campaign trail, Trump repeatedly said he would bring an end to the war within a day of taking office. Putin said Russia's goal is to remove what he called the root causes of the conflict in Ukraine and create conditions for lasting peace, according to the RBC news agency.

President Donald Trump said Russia and Ukraine would begin immediate negotiations to end their war following a two-hour phone call with Russian President Vladimir Putin on Monday, in the most concrete sign yet of a potential diplomatic opening.