President Donald Trump offered another glimpse of an emerging, sometimes contradictory foreign policy doctrine: trying to end various conflicts around the globe while vowing not to withdraw from the world entirely.

"We're in very serious negotiations with Iran for long-term peace," Trump said on a tour of the Gulf, according to a pool report by AFP. Fresh talks between Iranian and U.S. negotiators to resolve disputes over Tehran's nuclear programme ended in Oman on Sunday with further negotiations planned,