A defiant Iran has threatened to leave the international treaty that bars countries from obtaining atomic weapons and escalate its actions against the west, in response to US pressure and the threat of further sanctions.

Both Iran’s foreign minister, Mohammad Javad Zarif, and the speaker of parliament, Ali Larijani, warned on Monday that the country was considering exiting the five-decade Nuclear Non-Proliferation (NPT) if Europe takes Tehran before the United Nations Security Council over its alleged violations of the 2015 accord it signed with the west.

This comes after Iranian officials announced two impending launches of its Zafer surveillance satellites into space, in a development that worries non-proliferation experts who fear the delivery systems for putting a craft into orbit around the earth can also be used to launch long-range missiles.

Iran’s foreign ministry on Monday also repeated their threat to nations hosting US troops that they will be targets of Iranian reprisals if America uses their territory to stage attacks on the country.

In a sign of worsening ties with the UK, lawmakers passed a resolution calling on the government of President Hassan Rouhani to downgrade relations from the level of ambassador to charge d’affaires. This follows the brief detention of the UK ambassador to Iran, Robert Macaire, over his presence at a politically charged Tehran gathering for victims of a Ukrainian passenger plane shot down by an Iranian air defence personnel earlier this month.

Protests in Iran over downing of plane and tensions with the west Show all 23 1 /23 Protests in Iran over downing of plane and tensions with the west Protests in Iran over downing of plane and tensions with the west Anti-government protest at Amirkabir University Iranian police officers take position while protesters gather in front of Amir Kabir University AP Protests in Iran over downing of plane and tensions with the west Anti-government protest at Amirkabir University Iranians demonstrate following a tribute for the victims of the Ukraine Boeing 737 crash in front of the Amirkabir University in the capital Tehran EPA Protests in Iran over downing of plane and tensions with the west Anti-government protest at Amirkabir University Iranian police dispersed students chanting "radical" slogans during a gathering in Tehran to honour the 176 people killed when an airliner was mistakenly shot down AFP via Getty Protests in Iran over downing of plane and tensions with the west Anti-government protest at Amirkabir University - People hold flowers as tear gas fired by police rises Online videos purported to show that Iranian security forces fired both live ammunition and tear gas to disperse demonstrators protesting against the Islamic Republic's initial denial that it shot down a Ukrainian jetliner AP Protests in Iran over downing of plane and tensions with the west Anti-government protest at Amirkabir University Iranian police officers take position while protesters gather AP Protests in Iran over downing of plane and tensions with the west Anti-government protest at Amirkabir University AFP correspondents said hundreds of students had gathered early in the evening to pay respects to those killed in the air disaster ISNA/AFP via Getty Protests in Iran over downing of plane and tensions with the west Anti-government protest at Amirkabir University Iranian protester prepares to throw a tear gas canister back at police AP Protests in Iran over downing of plane and tensions with the west Anti-government protest at Amirkabir University A protester confronts an Iranian police officer AP Protests in Iran over downing of plane and tensions with the west Anti-government protest at Amirkabir University epa08120223 Iranians protest to show their sympathy with victims of Ukraine International Airlines Boeing 737-800 in front of the Amir Kabir University in Tehran, Iran, 11 January 2020. Media reported that hundreds of Iranians protests in Tehran in solidarity with victims of the Ukraine plane as Iranian military released a statement claiming that Ukraine International Airlines flight PS752 was shot down due to human error. EPA/ABEDIN TAHERKENAREH ABEDIN TAHERKENAREH EPA Protests in Iran over downing of plane and tensions with the west Anti-government protest at Amirkabir University Iranian police officers take position while protesters gathe AP Protests in Iran over downing of plane and tensions with the west Anti-government protest at Amirkabir University Iranians light candles for victims EPA Protests in Iran over downing of plane and tensions with the west Anti-government protest at Amirkabir University epa08120526 Iranians protest to show their sympathy to victims of Ukraine International Airlines Boeing 737-800 in front of the Amir Kabir University in Tehran, Iran, 11 January 2020. The Iranian military released a statement on 11 January 2020 that Ukraine International Airlines flight PS752 was shot down due to 'human error.' The passemger jet en route from Tehran to Kiev crashed minutes after takeoff on 08 January 2020, all all 167 passengers and nine crew members aboard were killed. EPA/ABEDIN TAHERKENAREH ABEDIN TAHERKENAREH EPA Protests in Iran over downing of plane and tensions with the west British embassy protest in Tehran People burn British and Israeli flags during a protest in front of the British embassy, in Tehran. Hundreds of Iranian hardliners gathered for a protest against Britain, a day after the UK ambassador to Iran Robert Macaire was detained after attending a a vigil for the victims of Ukraine passenger jet EPA Protests in Iran over downing of plane and tensions with the west British embassy protestBritish embassy protest in Tehran Chanting "Death to Britain", up to 200 protesters rallied outside the mission a day after the brief arrest of British ambassador Rob Macaire AFP via Getty Protests in Iran over downing of plane and tensions with the west British embassy protest in Tehran epa08122502 Iranian hardliners shout slogans as they gather in front of the British embassy during an anti-Britain protest, in Tehran, Iran, 12 January 2020. According to reports, hundreds of Iranian hardliners gathered for a protest against Britain, a day after the UK ambassador to Iran Robert Macaire was detained after attending a a vigil for the victims of Ukraine passenger jet. EPA/ABEDIN TAHERKENAREH ABEDIN TAHERKENAREH EPA Protests in Iran over downing of plane and tensions with the west British embassy protest in Tehran Iranian demonstrators hold placards bearing the images of slain military commander Qasem Soleimani and Iran's Supreme Leader Ayatollah Ali Khamenei in front of the British embassy in the capital Tehran on January 12, 2020 following the British ambassador's arrest for allegedly attending an illegal demonstration. - Chanting "Death to Britain", up to 200 protesters rallied outside the mission a day after the brief arrest of British ambassador Rob Macaire at a memorial for those killed when a Ukraine airliner was shot down. (Photo by ATTA KENARE / AFP) (Photo by ATTA KENARE/AFP via Getty Images) ATTA KENARE AFP via Getty Images Protests in Iran over downing of plane and tensions with the west Protesters chant slogans and hold up posters of Gen. Qassem Soleimani while burning representations of British and Israeli flags, during a demonstration in front of the British Embassy in Tehran, Iran, Sunday, Jan. 12, 2020. A candlelight ceremony late Saturday in Tehran turned into a protest, with hundreds of people chanting against the country's leaders â€” including Supreme Leader Ayatollah Ali Khamenei â€” and police dispersing them with tear gas. Police briefly detained the British ambassador to Iran, Rob Macaire, who said he went to the Saturday vigil without knowing it would turn into a protest. (AP Photo/Ebrahim Noroozi) Ebrahim Noroozi AP Protests in Iran over downing of plane and tensions with the west British embassy protest in Tehran epa08122741 Iranian hardliners gather in front of the British embassy during an anti-Britain protest, in Tehran, Iran, 12 January 2020. According to reports, hundreds of Iranian hardliners gathered for a protest against Britain, a day after the UK ambassador to Iran Robert Macaire was detained after attending a a vigil for the victims of Ukraine passenger jet. EPA/ABEDIN TAHERKENAREH ABEDIN TAHERKENAREH EPA Protests in Iran over downing of plane and tensions with the west A hardline protester holds up a placard during a demonstration in front of the British Embassy in Tehran, Iran, Sunday, Jan. 12, 2020. A candlelight ceremony late Saturday in Tehran turned into a protest, with hundreds of people chanting against the country's leaders â€” including Supreme Leader Ayatollah Ali Khamenei â€” and police dispersing them with tear gas. Police briefly detained the British ambassador to Iran, Rob Macaire, who said he went to the Saturday vigil without knowing it would turn into a protest. (AP Photo/Ebrahim Noroozi) Ebrahim Noroozi AP Protests in Iran over downing of plane and tensions with the west British embassy protest in Tehran epa08122743 Iranian hardliners gather in front of the British embassy during an anti-Britain protest, in Tehran, Iran, 12 January 2020. According to reports, hundreds of Iranian hardliners gathered for a protest against Britain, a day after the UK ambassador to Iran Robert Macaire was detained after attending a a vigil for the victims of Ukraine passenger jet. EPA/ABEDIN TAHERKENAREH ABEDIN TAHERKENAREH EPA Protests in Iran over downing of plane and tensions with the west British embassy protest in Tehran epa08122745 Iranian hardliners gather in front of the British embassy during an anti-Britain protest, in Tehran, Iran, 12 January 2020. According to reports, hundreds of Iranian hardliners gathered for a protest against Britain, a day after the UK ambassador to Iran Robert Macaire was detained after attending a a vigil for the victims of Ukraine passenger jet. EPA/ABEDIN TAHERKENAREH ABEDIN TAHERKENAREH EPA Protests in Iran over downing of plane and tensions with the west British embassy protest in Tehran epa08122786 Iranian hardliners gather in front of the British embassy during an anti-Britain protest, in Tehran, Iran, 12 January 2020. According to reports, hundreds of Iranian hardliners gathered for a protest against Britain, a day after the UK ambassador to Iran Robert Macaire was detained after attending a a vigil for the victims of Ukraine passenger jet. EPA/ABEDIN TAHERKENAREH ABEDIN TAHERKENAREH EPA Protests in Iran over downing of plane and tensions with the west Protesters chant slogans while holding up posters of Gen. Qassem Soleimani during a demonstration in front of the British Embassy in Tehran, Iran, Sunday, Jan. 12, 2020. AP

There were also reports that Kataib Hezbollah, an Iraqi militia affiliated with Iran, was setting up a new base on the Iraqi-Syrian border just weeks after the group was struck by US missiles.

Taken together, the series of warnings and threatens signalled that Tehran was countering a devastating economic and military pressure campaign spearheaded by the administration of US president Donald Trump by upping its belligerence on all matters of international concern: its nuclear programme, its missiles, its entanglements abroad, and its treatment of foreign nationals and diplomatic outposts within its borders.

The threats and the hardening of Iran’s positions follows the decision last week by the UK, Germany and France to trigger a legal mechanism that would take their dispute to the UN Security Council, which in practice could almost certainly end up unravelling the 2015 landmark nuclear deal and result in even harsher sanctions on the country.

The Europeans were responding to Iran’s decision to remove all limits on its enrichment of nuclear fuel as proscribed by the Joint Comprehensive Plan of Action following the US assassination of Revolutionary Guard commander Qassem Soleimani outside the international airport compound in the Iraqi capital of Baghdad on 3 January.

Foreign minister Mohammad Javad Zarif (centre) arrives prior to a meeting with his Venezuelan counterpart in Tehran (AP)

Iran responded by launching a barrage of missiles at two US bases in Iraq, injuring at least eight American military personnel while prompting complaints by Iraqi officials that Iran had violated its sovereignty. Iranian officials have been unapologetic.

“If the security and military specialists in Iran conclude that a country or regime has collaborated and helped this cowardly act, it will pay the price,” Foreign Ministry spokesman Seyed Abbas Mousavi told reporters in Tehran on Monday. “We are not after war but we are ready to strongly defend against any mischief.”

US Iran policy envoy Brian Hook insisted last week that “the combination of maximum economic pressure and restoring deterrence by the credible threat of military force” would “advance peace and stability in the region”.

But experts warn that an Iranian departure from the NPT would have disastrous consequences for the region, triggering an atomic arms race in one of the most volatile regions of the world. Pakistan, India and North Korea all exited the pact as they became nuclear weapons states while Israel, an undeclared nuclear power, never signed it.

Iran has threatened before to leave, but the latest warning comes amid unprecedented domestic and international pressure on the country.

“If the Europeans continue to play more political games, we will have many options,” Mr Zarif was quoted as saying.

Iran was among the original signers of the 1970 accord, which gives non-nuclear weapons states access to atomic technology in exchange for not pursuing a bomb.

But in 2003 it was found in “non-compliance” with the deal after it became known that the country had launched a secret programme to enrich uranium, one of the pathways towards obtaining a nuclear weapon, as well as producing nuclear energy.

Iran says its nuclear programme is meant only for peaceful civilian purposes, including energy and medicine. But western intelligence officials believe that Iran was actively pursuing a secret nuclear weapons programme until about 2003, when Saddam Hussein was toppled in the US invasion of Iraq.

Since then, most independent non-proliferation specialists have concluded that Iran had been pursuing a policy of nuclear ambiguity, assembling the various components to have a weapons programme without violating the NPT.

The 2015 nuclear deal was meant to place stricter limits on Iran’s nuclear programme in exchange for economic incentives. But Mr Trump’s abrogation of the agreement and European companies’ abidance of American restrictions have robbed it of incentives to keep lids on its nuclear programme.

The president and the small clique of Washington hawks who have his ear on Iran say that the nuclear deal gave Tehran too much in return for limits on its nuclear programme which would expire by 2030.

European officials say they want to preserve the deal which they consider a landmark diplomatic agreement. They say they triggered the dispute mechanism, which could bring Iran’s nuclear programme before the Security Council for renewed sanctions, to keep Iran from further expanding its nuclear activities.