Several Republican and Democratic senators have defended NATO after President Donald Trump suggested he was “absolutely” considering withdrawing the United States from the alliance.

Lawmakers including Mitch McConnell and Thom Tillis argued that NATO has supported the U.S. in past conflicts and remains vital to national security.

They warned that leaving the alliance would weaken U.S. interests and could benefit adversaries such as Russia and China.

Trump’s comments followed tensions over NATO’s involvement in the U.S.-led campaign alongside Israel against Iran, The Guardian has reported.

Under current law, withdrawing from NATO would require significant congressional approval, making such a move politically difficult.