Joe Biden said the US would not supply F-16 fighter jets to Ukraine, in a brief exchange with reporters. Ukraine had begun a high-profile lobbying campaign for the fighters, manufactured by the US defence company Lockheed Martin, almost immediately after Germany and the US said they would supply their own tanks to Ukraine for the first time. Other European leaders had indicated they were open-minded about supplying jets, as Ukraine tries to build up a fighting force based increasingly on western arms to break through Russian lines. Ukraine says Poland has sent “positive signals” about supplying its own F-16s after Warsaw’s prime minister announced plans to lift the country’s defence spending to 4% of GDP. Ukrainian air force spokesperson has said it would take its pilots about six months to train on such fighter jets. UK defence secretary wryly noted that “the initial response is no and it ends up being yes”.