A top USinfo-icon general on Tuesday signalled support for the Iraninfo-icon nuclear deal, saying the agreement, which President Donald Trumpinfo-icon has threatened to withdraw from, has played an important role in addressing the Islamic republic's nuclear programme.

"The JCPOA addresses one of the principle threats that we deal with from Iran, so if the JCPOA goes away, then we will have to have another way to deal with their nuclear weaponsinfo-icon program," said US Armyinfo-icon General Joseph Votel.

JCPOA, or Joint Comprehensive Plan of Action, is the formal name of the accord reached with Iran in July 2015 in Vienna.

Trump has threatened to withdraw the United Statesinfo-icon from the accord between Tehraninfo-icon and six worldinfo-icon powers unless Congress and European allies help "fix" it with a follow-up pact. Trump does not like the deal's limited duration, among other things.

Votel is head of the US military's Central Command, which is responsible for the Middle Eastinfo-icon and Central Asiainfo-icon, including Iran. He was speaking to a Senate Armed Services Committee hearing on the same day that Trump fired Secretary of State Rex Tillerson after a series of public rifts over policy, including Iran.

Mike Pompeo is to replace Tillerson and his appointment may be positively received by traditional US allies in the Middle East, some of whom viewed Tillerson with suspicion over his closeness to Qatarinfo-icon and after he joined Defence Secretary Jim Mattis in pressing a sceptical Trump to stick with the agreement with Iran.

"Now Secretary of State Pompeo, UN ambassador [Nikki Haley], and the president are all, on foreign policyinfo-icon, going to play the same tune on Iran," said Iranian-American journalist Negar Mortazavi to Middle East Eye.

When a lawmaker asked whether he agreed with Mattis and Chairman of the Joint Chiefs of Staff General Joseph Dunford's position on the deal, Votel said: "Yes, I share their position."

Mattis said late last year that the United States should consider staying in the Iran nuclear deal unless it was proven Tehran was not complying or that the agreement was not in the US national interest.