Washington is ready to expand arms supplies to Ukraine in order to build up the country's naval and air defense forces, U.S. Department of State Special Representative for Ukraine Kurt Volker has said in the interview with the Guardian edition.

"They are losing soldiers every week defending their own country. And so in that context it's natural for Ukraine to build up its military, engage in self-defense, and it's natural to seek assistance and is natural that other countries should help them. And of course they need lethal assistance because they're being shot at," he stated.

"We can have a conversation with Ukraine like we would with any other country about what do they need. I think that there's going to be some discussion about naval capability because as you know their navy was basically taken by Russia. And so they need to rebuild a navy and they have very limited air capability as well. I think we'll have to look at air defense," the official added.

Volker said there was still a substantial gap between the U.S. and Russia over how a United Nations peacekeeping force could be deployed to end the four-year war.

In May, the Congress approved $250 million in military assistance to Ukraine in 2019, including lethal weaponry.