Trump called the vote "meaningless" and said it had "bad timing" in a post on Truth Social.
Four Republicans voted with Democrats, and Trump criticized them.
The initiative, approved by the House of Representatives earlier in June, cannot be stopped, but Democrats and Republicans have different views on whether it is legally binding or of a more symbolic nature.
The vote took place shortly after the US and Iran reached a memorandum of understanding aimed at ending the war that the US and Israel launched against Iran on February 28.
