The US administration is concerned that American-linked ships and US oil supplies have been targeted by Kiev during the Ukraine conflict, US Secretary of State Marco Rubio said.

"On the other hand, it is having an impact. The one thing we are concerned about, however, is that over the last few months, on a number of occasions, American-linked ships, American oil supplies, have been targeted. Probably not deliberately, but targeted nonetheless by Ukraine. And so that's something that needs to be addressed. We can't have that happen. But obviously, you know, look, that's why the president has always wanted to end this war and is prepared to do anything he can to bring it to an end. It's been difficult, but we remain hopeful that something can happen there," Rubio said in an interview with Fox News.