Few expect substantial progress toward peace at a new round of negotiations between Russia and Ukraine. But with a new deadline from US President Donald Trump for a deal, analysts say each side wants to show Washington that it is constructively seeking peace – and that other side is not.

U.S. President Donald Trump's decision to ramp up arms shipments to Ukraine is a signal to Kyiv to abandon peace efforts, Russia said on Thursday, vowing it would not accept the "blackmail" of Washington's new sanctions ultimatum.