The United States is working on a deal to give some of Poland’s fighter jets to Ukraine, White House officials have said.

       US secretary of state Antony Blinken explained the plan at a press conference in Moldova on Sunday.

       “We’re looking actively now at the question of airplanes that Poland may provide to Ukraine,” Mr Blinken said. “How quickly might that happen? I can’t speak to a timeline.”

       The proposal, which has not yet been finalised, would be for Poland to donate some of its Soviet-era MiG planes to Ukraine’s military, and then for the US to give Poland newer, American-made F-16 jets to replace them.

       For Ukraine, the Soviet-era planes are in some ways more useful because Ukrainian pilots have been trained to use the Russian-style jets.

       Recommended Ukraine-Russia war news: Zelensky responds to nuclear plant attack Why has Russia invaded Ukraine? The conflict explained Sign The Independent’s petition to help the people of Ukraine

       An unnamed White House spokesperson later confirmed to NBC News that the US and Nato were hammering out the details.

       “We are working with the Poles on this issue and consulting with the rest of our NATO allies,” the spokesperson said.

       The Russian invasion of Ukraine is now in its third week. The United Nations has estimated that at least 227 Ukrainian civilians have been killed, and more than 1.2 million have fled the country. On Sunday, reports emerged that Russian soldiers were either intentionally or accidentally firing on evacuees.

       Ukraine’s president, Volodymyr Zelensky, has urgently pleaded for more military aid from Western countries. On Saturday, he spoke via Zoom with members of US Congress, demanding more jets, a ban on importing Russian oil, and a no-fly zone over Ukraine.

       As one congressman who was at the meeting explained, the Polish jets proposal was a major part of the conversation.

       “His main ask was for the U.S. to allow Poland and Romania to transfer Soviet era jets to #Ukraine, and for the US to compensate by giving more advanced planes to those two NATO allies,” Rep Brad Sherman tweeted. “This is much safer than a ‘no fly zone’ as it doesn’t involve Americans killing Russians.”