Video report by ITV News Correspondent Rachel Younger
Iran's President has accused the US of fuelling tensions in an already volatile region after National Security Advisor and long-time Iran hawk John Bolton warned of an attack.
Hassan Rouhani blamed the “interventionalist military presence” of the US for the Middle East’s problems, according to the official IRNA news agency on Sunday.
President Rouhani also said Iran expects “international bodies to show proper reaction” to what he called an “invasion move” after Iran’s military shot down a US drone Tehran insists was in Iranian airspace.
However, the US claims the drone was flying over international waters.
In response to the shooting down of the drone, US President Donald Trump ordered US military cyber forces to target Iranian military computer systems on Thursday.
Iran says it chose not to fire on a manned US military aircraft flying in the area at the same time as the downed drone – a decision Trump praised.
President Rouhani’s remarks came just hours after Mr Bolton warned Iran that it should not "mistake US prudence and discretion for weakness”.
Speaking alongside Israeli Prime Minister Benjamin Netanyahu in Jerusalem on Sunday, Mr Bolton added no one has granted Iran a “hunting license in the Middle East”.
Mr Bolton, who backed the Iraq war and has previously advocated strikes on Iran and North Korea, said sanctions will continue against Tehran and that the US reserves the right to attack it at a later point.
President Trump claimed on Twitter that he backed away from plans for a more conventional strike 10 minutes before it was due to take place after learning around 150 Iranians would be killed.
After telling reporters on Thursday that it was “hard to believe” the hit on the US drone was intentional, President Trump accused Iran of “knowingly” targeting the plane two days later.
Mr Bolton emphasised that President Trump had only “stopped the strike from going forward at this time”.
As he left the White House on Saturday for a weekend at his Camp David retreat, President Trump said: “The fact is we’re not going to have Iran have a nuclear weapon.
“And when they agree to that, they are going to have a wealthy country, they’re going to be so happy and I’m going to be their best friend.
“I hope that happens. I hope that happens, but it may not.”
President Trump later said Iran will be hit with unspecified new sanctions on Monday.
Iran's semi-official Fars news agency on Sunday quoted General Gholamali Rashid as saying the Trump administration "should behave in a responsible way to protect the lives of American forces".
Gen Rashid said if war happens, its scope and duration could not be controlled, and blamed any escalation on “US interventionist policy”.
The general oversees and coordinates joint military operations in the Iranian Armed Forces.
Tensions between Iran and the US have been growing for more than a year, after Mr Trump pulled out of a long-term deal struck with the country in 2015 to limit its sensitive nuclear activities and allow in international inspectors in return for the lifting of economic sanctions.
The deal was signed by his predecessor Barack Obama along with the UK, France, China, Russia and Germany, which still support the agreement.
But Mr Trump declared it a "terrible" deal and imposed more sanctions, crippling Iran's economy.
Tensions between the US and Iran have increased further in recent weeks amid claims by Washington that Tehran has been behind attacks on oil tankers in the Persian Gulf.
Iran has denied the claims.
On Sunday, former Labour foreign secretary David Miliband warned of the prospects of a "hot war" between Iran and the US as well as possible "contagion" across the region.
The former Labour MP described the situation as a "pressing global threat to peace and security".
He told BBC One's The Andrew Marr Show: "We should be very worried about the prospect, the real prospect, of a hot war between Iran and the US, we were ten minutes away from that on Thursday night.
"There are people in the senior reaches of the US administration who want a war with Iran, they've said so very clearly, and there are some people on the Iranian side who are itching to get at the Americans too, partly for domestic reasons.
"[What] you've got to understand is that a war between the US and Iran will not be restricted to the US and Iran, it will be a contagion right across a conflagration...
"Afghanistan is an obvious flashpoint, Iraq is an obvious flashpoint."
He added: "I think we should be very worried and we need some very active diplomacy...
"We're relying on the caution of President Trump to keep the hawks at bay in his own administration."
Meanwhile Foreign Secretary Jeremy Hunt has said the current Tory leadership race, in which he is battling Boris Johnson, is not stopping him from carrying out his role, and that he is doing what he can amid the heightened tensions.
Mr Miliband warned Mr Hunt that he cannot be "completely absent from the stage".
In response the South West Surrey MP said he is speaking to his counterparts "regularly" about the Iran crisis which he called "extremely serious".
Foreign Office minister Andrew Murrison held talks with the Tehran government at the weekend where he said he was "clear" about the UK's concerns over Iran's activities.
He added: "I reiterated the UK's assessment that Iran almost certainly bears responsibility for recent attacks on tankers in the Gulf of Oman.
"Such activity, which carries a high risk of miscalculation, needs to stop to allow for immediate de-escalation of rising tensions.
"And I was clear that the UK will continue to play its full part alongside international partners to find diplomatic solutions to reduce the current tensions.
"I reiterated the UK's determination to maintain the nuclear deal which is in our shared security interests.
"I was clear that Iran must continue to meet its commitments under the deal in full - including the limits imposed on its low-enriched uranium stockpile."
The trip was announced after Donald Trump said the US was "cocked and loaded" to retaliate against Iran for downing an American drone.
On Saturday, a spokesperson for Iran's armed forces warned that a military strike would "set the region ablaze and burn up the US, its interests, and its allies".
Mr Trump later tweeted that the US will impose "major additional sanctions" on Iran on Monday after opting to halt military action "from going forward at this time".