The discussion comes after a letter was sent to the White House by a number of members of Congress warning President Joe Biden that he may have to alter his Ukraine strategy and “directly engage” with Russian leader Vladimir Putin.
Mr Blinken tweeted: “Connected with Dmytro Kuleba again today.
“It is important to once again emphasize that US support for Ukraine is concrete, comprehensive, and enduring.”
Meanwhile, Mr Kuleba tweeted: “Detailed and candid discussion with Secretary Blinken on ways to end Russia’s nuclear blackmail.
“Grateful for affirming the unfaltering US support whatever circumstances are.
“Euro-Atlantic solidarity with Ukraine is essential. We also focused on deliveries of air defence and ammo.”
MORE TO FOLLOW…