The 15-member body was set to vote on a draft resolution brought by Bahrain on authorising the use of "defensive" force to protect shipping in Hormuz from Iranian attacks.
Tehran has kept the pressure on Israel and its Gulf Arab neighbour, despite US and Israeli insistence that Iran's military capabilities have been all but destroyed.
Another US-Israeli attack on Tuesday hit one of the largest pharmaceutical companies in Iran, Tofigh Daru, which produces anaesthetic and cancer drugs, according to the Iranian government.
The ouster, reported earlier by CBS News, is just the latest of more than a dozen firings of top generals and admirals by Hegseth since he took office last year.
