Iran’s president has accused the United States of fuelling tensions in an already volatile region, as the crisis between the two countries escalates.

The official IRNA news agency quoted Hassan Rouhani as saying the “interventionist military presence” of the US is responsible for the Middle East’s problems.

Mr Rouhani also denounced what Iran alleges was the incursion of its airspace by a US military drone, which Tehran shot down on Thursday.

Mr Rouhani said: “We expect international bodies to show proper reaction to the invasion move.”

His remarks came during a meeting with the president of IPU, or Inter-Parliamentary Union, Gabriela Cuevas, in Tehran.

Earlier, US National Security Adviser John Bolton said Iran should not “mistake prudence and discretion for weakness,” after the US abruptly called off military strikes.

Mr Bolton’s tough message seemed to be aimed not only at Iran, but also at reassuring key US allies that the White House remains committed to maintaining pressure on the country.

Israel, along with Arab countries in the Gulf, considers Iran to be its greatest threat, and President Donald Trump’s last-minute about-face appears to have raised questions about US willingness to use force against the Islamic Republic.

The downing of the aircraft on Thursday marked a new high in the rising tensions between the United States and Iran in the Persian Gulf.

The Trump administration has vowed to combine a “maximum pressure” campaign of economic sanctions with a buildup of American forces in the region, following the US withdrawal from the 2015 nuclear deal between Iran and world powers.

Mr Trump said he backed away from the planned strikes after learning 150 people would be killed.

But Mr Bolton emphasised that the US reserved the right to attack at a later point. He also said a new set of sanctions on Iran are expected to be announced on Monday.

Israel Persian Gulf-Tensions
US National Security Adviser John Bolton alongside Israeli Prime Minister Benjamin Netanyahu (Tsafrir Abayov/AP)

“No one has granted them a hunting licence in the Middle East. As President Trump said on Friday our military is rebuilt, new and ready to go,” Mr Bolton said in Jerusalem alongside Israeli Prime Minister Benjamin Netanyahu, himself a vocal critic of Iran over the years.

“And as he made clear yesterday, referring to his earlier remarks, ‘I just stopped the strike from going forward at this time,'” Mr Bolton added.

Mr Bolton is visiting Israel for three-way talks with his Israeli and Russian counterparts that are expected to focus on Iranian involvement in conflicts across the region, including in neighbouring Syria.

Israel’s prime minister has been a vocal critic of Iran over the years, accusing the Islamic Republic of sinister intentions at every opportunity.

But Mr Netanyahu, a longtime critic of the nuclear deal, has remained uncharacteristically quiet throughout the current crisis between the US and Iran. The Israeli leader appears to be wary of being seen as pushing the US into a new Middle Eastern military conflict.

Standing alongside Mr Bolton, Mr Netanyahu sided with the Americans. He said Iranian involvement in conflicts across the region had increased as a result of the nuclear deal, which gave the country a new cash infusion, and had nothing to do with the US exit from the agreement.

“After the deal, but before recent events, Iran has been on a campaign of aggression,” he said.

“Those who describe the recent actions as somehow opening a hornet’s nest are living on another planet.”

Mr Netanyahu made no mention of the called-off airstrike and said he was “pleased” by US plans for increased economic pressure.

A top Iranian military commander warned on Sunday that any conflict with Iran would have uncontrollable consequences across the region and endanger the lives of US forces.

Major General Gholamali Rashid’s remarks, published by the semi-official Fars news agency, were made while addressing Iran’s powerful Revolutionary Guards Corps during a field visit to a command centre for Iranian radars and missile systems. The general oversees and coordinates joint military operations in the Iranian Armed Forces.

US military cyber forces on Thursday launched a strike against Iranian military computer systems, according to US officials. The cyberattacks disabled Iranian Revolutionary Guard Corps computer systems that controlled its rocket and missile launchers, the officials said.

Throughout the recent crisis, Mr Trump has wavered between aggressive language and actions towards Iran and a more accommodating tone. His administration is aiming to cripple Iran’s economy and force policy changes by re-imposing sanctions, including on Iranian oil exports.

Donald Trump
Donald Trump has warned military action against Iran is still an option (Susan Walsh/AP)

However, Mr Trump said on Saturday he appreciated that Iran did not fire on a US spy plane with a crew of over 30 people that was flying on Thursday over the same area as the drone that was shot down.

He also dangled the prospect of eventually becoming an unlikely “best friend” of America’s longtime Middle Eastern adversary.

Iranian legislators on Sunday chanted “death to America” during an open session when acting parliament speaker Masoud Pezeshkian condemned what he said was the violation of Iranian airspace by the US drone.