A Foreign Office minister is to visit Iran on Sunday and call for “urgent de-escalation in the region”, amid heightening tensions between Tehran and Washington after an unmanned American drone was shot down.

Andrew Murrison, the MP for South West Wiltshire who covers the Middle East as part of his brief, will raise UK and international concerns about Iran’s “regional conduct and its threat to cease complying with the nuclear deal to which the UK remains fully committed” during “frank and constructive” talks with the government in Tehran.

“At this time of increased regional tensions and at a crucial period for the future of the nuclear deal, this visit is an opportunity for further open, frank and constructive engagement with the government of Iran,” the Foreign Office said.

Iran claimed the downed aircraft was “spying” in its airspace and had crossed a “red line”. However, Washington said the incident had occurred in international airspace.

UK relations with Iran have been dominated by the ongoing imprisonment of Nazanin Zaghari-Ratcliffe, the British-Iranian national who has always denied the spying allegations upon which she has been held in Iran since 2016.

Speaking about Murrison’s planned visit to Iran, her husband Richard Ratcliffe said: “I’ve been asked how hopeful I am. I’m not sure if I’m hopeful, but certainly will be watching very closely to see how things develop and what comes back.”

Ratcliffe is on day eight of a hunger strike outside the Iranian embassy in London in solidarity with Zaghari-Ratcliffe. “[Murrison will] be talking to the foreign ministry; we’ll be looking to see what reaction comes from inside the prison to those conversations,” Ratcliffe said.

“The sooner the British government’s able to work with the Iranian government and find a resolution, that’s better for our family, for sure.”

However, US-Iran relations have overshadowed her ongoing confinement, and while both countries have said they do not have any appetite for conflict Donald Trump told NBC on Friday that if it comes, Iran would experience “obliteration like you’ve never seen before ... but I’m not looking to do that”.

Trump said the US was “cocked and loaded” to retaliate against Iran, but that he had cancelled planned strikes just minutes before they were to be carried out on Thursday after being told 150 people could die.

Iran has vowed to defend its borders. “Regardless of any decision [US officials] make… we will not allow any of Iran’s borders to be violated,” the foreign ministry spokesman Abbas Mousavi, told Tasnim, a semi-official news agency. “Iran will firmly confront any aggression or threat by America.”

Timeline Recent tensions in the Gulf Show The UAE says four commercial ships off its eastern coast 'were subjected to sabotage operations'. Yemen's Houthi rebels launch a drone attack on Saudi Arabia, striking a major oil pipeline and taking it out of service. Saudi Arabia subsequently blames Iran for the attack. A rocket lands near the US embassy in the Iraqi capital, Baghdad, without harming anyone. It's not clear who is behind the attack, but after the initial reports, Donald Trump tweets: 'If Iran wants to fight, that will be the official end of Iran. Never threaten the United States again!' Saudi Arabia says 26 people were wounded in an attack by Yemen's Houthi rebels on an airport in the kingdom's south-western town of Abha. Two oil tankers near the strategic strait of Hormuz were reportedly attacked in an assault that left one ablaze and adrift. 44 sailors were evacuated from both vessels and the US navy assisted. Iran’s Revolutionary Guards say they have shot down what they called a US 'spy' drone they claim was flying in in the country’s airspace. The US military confirm one of its drones has been taken down, but say it was in international airspace. Donald Trump reportedly gives approval for the US military to launch strikes on Iran in retaliation for the loss of the drone, before pulling back at the last minute. The Iranian and US presidents trade insults, with Hassan Rouhani suggesting that Donald Trump suffered from a “mental disorder” and Trump once more threatening Iran with “obliteration”. Iran summons UK ambassador over an incident off Gibraltar as Royal Marines seize a tanker, Grace 1, the UK suspects of carrying oil to Syria. The International Atomic Energy Agency, the body tasked with verifying Iranian compliance with the terms of the nuclear deal, verifies that Tehran has breached the agreed 3.67% limit for enriched uranium. The UK government says three Iranian boats were warned off by the frigate HMS Montrose after Iranian boats 'attempted to impede' a British oil tanker in strait of Hormuz. Tehran denies involvement. In a major escalation, Iran seizes the Stena Impero, a British-flagged tanker, off its coast. Iranian officials later make it clear that the capture was in retaliation for the capture of the Iranian supertanker Grace 1 earlier in July. Despite US attempts in the courts to prevent it, Gibraltar says it will free oil tanker at centre of the Iran row. Iran gives assurances the oil is not destined for Syria, where selling it would breach international sanctions against Britain accuses Iran of breaching those assurances after Tehran acknowledged the oil had been sold, and the reflagged tanker Adrian Darya 1, previously known as Grace 1, had reached its final destination after the ship was photographed off the coast of Syria.

Last year, the US unilaterally pulled out of the 2015 nuclear deal between Iran and six other powers and reimposed sanctions on the country. International sanctions had been lifted under the pact in return for Tehran curbing its nuclear programme.

A senior Arab diplomat said sharply increased tensions would further harm the crisis-hit Middle East region.

“De-escalation is very important because tempers are flaring… It’s very important we avoid confrontation right now,” they told Reuters, on condition of anonymity. “Confrontation, whatever we think about Trump or Iran, will be disastrous for everyone.”

On Saturday, Etihad Airways followed Qantas, British Airways, Lufthansa and a number of other airlines and suspended “until further notice” operations through Iranian airspace over the Straits of Hormuz and the Gulf of Oman.

The United Arab Emirates-based carrier said “the safety of our passengers and staff is the highest priority” and that it would use alternative flight paths on a number of routes to and from Abu Dhabi.

The US has warned that commercial airliners could be mistakenly attacked after the US Navy Global Hawk drone was shot down on Thursday.

Tehran dismissed the concerns, which come 30 years after the US Navy accidentally shot down an Iranian civilian flight flying in Iranian airspace, killing almost 300 people.