(Reuters) - Russia's Foreign Ministry summoned senior U.S. diplomats on Friday to protest against remarks by White House national security adviser Jake Sullivan, whom it accused of "effectively endorsing strikes" on Crimea.
The peninsula on the Black Sea was seized by Russia and unilaterally annexed from Ukraine in 2014, but is internationally recognised as Ukrainian territory.
"It is time for Washington to learn that any form of aggression against Russia will continue to be met with the strongest possible response," the ministry said.
It did not specify which comments it objected to, but when Sullivan was asked in a CNN interview on Sunday whether Ukraine should have weapons that can reach Russian targets in Crimea, he replied:
"Yes. We have not placed limitations on Ukraine being able to strike on its territory within its internationally recognised borders.
"What we have said is that we will not enable Ukraine with U.S. systems, Western systems, to attack Russia. And we believe Crimea is Ukraine."
Russia has reported a series of drone strikes and attacks within its internationally recognised territory in recent weeks, including a cross-border raid on Tuesday in the Belgorod region that it blamed on Ukrainian militants. Kyiv said it had nothing to do with the incident.