The US says it will allow its Western allies to supply Ukraine with advanced fighter jets, including American-made F-16s, in a major boost for Kyiv.

The Ukrainian capital Kyiv has been targeted by further Russian air attacks, described by one official as "exceptional in density".

Vladimir Putin has said Russia's future "rests on" the soldiers fighting in Ukraine, during his annual speech to mark Victory Day in Moscow.

"There is nothing more important now than your combat effort," he said.

The military parade, which commemorates the Soviet victory over Nazi Germany, was scaled back this year for security.

Air raid sirens have sounded across Ukraine after Russia launched a fresh wave of drone and missile strikes.

A drone strike has caused a massive fire at an oil depot in Russian-controlled Crimea, local officials say.

A wave of Russian air strikes on cities across Ukraine, including Kyiv, has left at least 25 people dead.