Russia said on Tuesday it was waiting for clarity from the United States about the possible supply of Tomahawk missiles to Ukraine, saying such weapons could theoretically carry nuclear warheads.
US President Donald Trump said on Monday he would want to know what Ukraine planned to do with Tomahawks before agreeing to provide them because he did not want to escalate the war between Russia and Ukraine.
He said, however, that he had "sort of made a decision" on the matter.
Asked about the comments, Kremlin spokesman Dmitry Peskov said: "We understand that we need to wait, probably, for clearer statements, if any come."
Peskov said that under Trump's predecessor Joe Biden, US practice had been to announce supplies of new weapons only once they had been delivered to Ukraine.
Russian President Vladimir Putin said in comments published on Sunday that if Washington supplied Tomahawk missiles to Ukraine for long-range strikes deep into Russia, it would lead to the destruction of Moscow's relationship with the US.
Peskov said it was important to realize that "if we abstract from various nuances, we're talking about missiles that could also be nuclear-capable. Therefore, this is truly a serious round of escalation."
Tomahawk missiles have a range of 2,500 km (1,550 miles), so Ukraine would be able to use them to strike targets anywhere in European Russia, including Moscow, if Trump gave the go-ahead to supply them.
