Ukraine has received fighter planes and aircraft parts to bolster its air force in the face of Russia’s invasion, the Pentagon said Tuesday, declining to specify the number of aircraft or their origin.

The announcement comes a week after US President Joe Biden unveiled an $800 million military aid package for Kyiv, including heavier equipment such as howitzers, as fighting escalates in eastern Ukraine.

The moves indicate a change in attitude in the West, which had initially refused to provide Ukraine with heavy armaments to avoid action Russia could consider direct involvement in the conflict.

Ukrainian forces “right now have available to them more fixed-wing fighter aircraft than they did two weeks ago”, - Pentagon spokesman John Kirby said.

“Without getting into what other nations are providing, they (Ukrainian forces) have received additional platforms and parts to be able to increase their fleet size”, - he said.

Kirby did not specify the type of aircraft delivered to the Ukrainian military, which had been pleading for warplanes for weeks, but suggested that they were Russian-made.

“Other nations who have experience with those kinds of aircraft have been able to help them get more aircraft up and running. While the US had helped with the shipment of some parts, it had not transported whole aircraft”, - Kirby said.