Britain will consider joining its “strongest ally” the United States in attacking Iran, Jeremy Hunt said.
The Foreign Secretary, who is battling to be the UK’s next Prime Minister, said the country would consider requests for military support “on a case-by-case basis.”
Mr Hunt was speaking amid feverish tensions between Tehran and Washington after Donald Trump admitted he called off an air strike against the Islamic Republic on Thursday in response to Iran shooting down an unmanned US drone.
Tory leadership candidate Jeremy Hunt said the UK government was “constantly in touch” with the US over the tense situation in the Gulf.
He said: “We will stand by the United States as our strongest ally but of course we have to consider any requests for military support on a case-by-case basis.
“We do strongly believe that the solution is for Iran to stop its destabilising activity throughout the Middle East and we are very concerned about the sabotaging of tankers that has happened recently, which is almost certainly Iran, and we’re constantly in touch with the United States.
“We want to de-escalate the situation but we are of course extremely worried.”
In recent years, British forces have joined their American counterparts in conflicts in Iraq, Afghanistan and Libya.
US President Trump today insisted he is "not looking for war" after a senior Iranian military chief warned any conflict in the Gulf could easily spiral out of control.
"I'm not looking for war," Trump told NBC's Meet the Press programme in an interview broadcast this afternoon.
"I think they want to negotiate. And I think they want to make a deal. And my deal is nuclear. Look, they're not going to have a nuclear weapon," he added
"I don't think they like the position they're in. Their economy is, is absolutely broken."
Relations in the region began to worsen significantly when Trump pulled out of a 2015 nuclear deal between Iran and six powers and reimposed sanctions on the country.
The sanctions had been lifted under the pact in return for Tehran curbing its controversial nuclear programme.
Iran has said it would respond firmly to any threat against it and warned earlier today of the risks of a military confrontation.
"If a conflict breaks out in the region, no country would be able to manage its scope and timing," Major General Gholamali Rashid said, according to the Fars news agency.
"The American government must act responsibly to protect the lives of American troops by avoiding misconduct in the region."
Iranian President Hassan has already accused the Americans of stoking tensions in the Gulf through what Iran has called the violation of its airspace by the US military drone.
Washington said the aircraft was targeted in international air space in "an unprovoked attack".
Speaking on a visit to Israel, US National Security Adviser John Bolton sought to maintain the military pressure on Iran.
"Neither Iran nor any other hostile actor should mistake U.S. prudence and discretion for weakness. No one has granted them a hunting license in the Middle East," he said.
Iran is feeling the effects of the sanctions, Bolton told reporters, adding Iran would never be allowed nuclear weapons.
"Sanctions are biting, and more added last night," he added.
"Iran can never have nuclear weapons - not against the USA and not against the world."
Mr Hunt insisted he is doing what he can amid the crisis in the Middle East.
The Foreign Secretary said he is speaking to counterparts "regularly" about the Iran crisis which he called "extremely serious".
Foreign Office minister Andrew Murrison is holding talks with the Tehran government today and is expected to call for "urgent de-escalation".
Earlier it was reported the US launched a cyber-strike on Iranian weapons systems after President Trump pulled out of an air attack on the hardline country.
The computer attack is said to have disabled the hi-tech operating systems controlling rocket and missile launchers in the Islamic Republic.
Insiders say the move was in retaliation for the shooting down of a US drone as well as attacks on oil tankers that the US has blamed Iran for.