US naval destroyers deployed in the eastern Mediterranean Sea joined Israeli attempts to head off the attack.
USS Bulkeley and the USS Cole both fired to intercept Iranian missiles, said General Pat Ryder, the Pentagon’s spokesman. The vessels were in the area as part of a bolstered presence aimed at monitoring tensions in the Middle East.
Donald Trump said Mr Biden and Ms Harris were leading the world “to the brink of World War III” because of their weak leadership.
He said the world “is on fire and spiralling out of control” and that “we have no leadership, no one running the country”.
A meeting of the emergency Cobra committee was held in Whitehall, after David Lammy, the Foreign Secretary, spoke to Ali Bagheri, his Iranian counterpart, to urge restraint.
The Foreign Office is not commenting on potential British involvement in helping Israel defend itself against Iranian missiles.
Earlier on Tuesday, Britons in Lebanon were warned that the UK could not guarantee getting them out quickly if the “febrile and fragile” situation deteriorated.
It is still hoped that a UK-chartered flight will leave Beirut on Wednesday to take British citizens out of the country. Britain is also seeking to buy dozens of seats on commercial airlines to help people leave.
Mr Lammy urged British nationals in Lebanon to leave, warning that the airport in Beirut could be closed if fighting continued.
Speaking to broadcasters at the Foreign Office, Mr Lammy said: “I have warned and cautioned now for months that we have seen, in previous crises between Israel and Lebanon, the airport close, and we cannot guarantee that we will be able to get people out in speedy fashion.
“And of course, this is now turning into a very, very concerning situation on the ground.”