US intelligence officials believe Iran and the Houthis are unlikely to launch pre-emptive escalatory attacks against American personnel or Israel at this stage.
Iran says diplomatic messages are still being exchanged through intermediaries, while conflicting claims over reopening the Strait of Hormuz have added uncertainty to efforts to ease tensions with Washington.
Iran has rejected claims that it offered to reopen the Strait of Hormuz in exchange for an end to the US naval blockade. Tehran has also disputed reports of a new proposal through Pakistani mediators, while the two sides continue to disagree over the terms of a possible deal.