Ukraine has received its first batch of US-made F-16 fighter jets, Ukrainian President Volodymyr Zelensky said on Sunday, quickly adding that more are needed to beat back Russian forces.

For more than two years, Ukraine has pleaded with its Western partners for the aircraft – long considered the crown jewel in the sprawling list of military hardware Kyiv has sought.

"We often heard the word 'impossible'. Now it is a reality. Reality in our skies. F-16s in Ukraine. We made it happen," Zelensky said, as some flew above him during the announcement.

Zelensky was standing in front of what looked like two grey, partially-covered F-16s branded with the Ukrainian trident, in a location reporters were asked not to disclose for security reasons.

"I am proud of all our guys who are mastering these aircraft and have already started using them for our country," he said.

He did not say how many jets had been delivered and declined to comment on their specific tasks, but journalists saw at least two F-16s on the spot.

The announcement was welcomed by many as Kyiv's forces are struggling to hold back advances by Russian troops.

"This is the combat aircraft we have been waiting for, which can significantly enhance our capabilities," said Parliament chairman Ruslan Stefanchuk.

Kyiv hopes the arrival of the fighter jets – touted for their precision, speed and range – will enable it to better protect itself from Russian bombardment. (AFP)