The seizure of the Stena Impero tanker in the Strait of Hormuz is the latest episode to contribute to rising tensions between the UK, US and Iran in the region.

After Donald Trump unilaterally withdrew the US from a long term nuclear agreement it had signed with five other world powers, tensions have worsened with Washington.

Iran has refused to negotiate any changes, and has threatened to further break the terms of the agreement if Europe does not help limit the effects of US sanctions. It has also broken restrictions on its production of enriched uranium, used to make reactor fuel but also potentially nuclear bombs.

Tensions between the UK and Iran flared up earlier this month when Royal Marines seized an Iranian tanker which was suspected of breaking European Union sanctions. The UK suspected Grace 1, detained near Gibraltar, was carrying oil bound for Syria.

Foreign secretary Jeremy Hunt said it would be released if Tehran guaranteed its oil would not be given to the country's president Bashar al-Assad's regime.

Tensions high as Trump approves new Iran sanctions: In pictures Show all 17 1 /17 Tensions high as Trump approves new Iran sanctions: In pictures Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, their surface-to-air missile is seen as it shoots down a US surveillance drone EPA Tensions high as Trump approves new Iran sanctions: In pictures This photo shows US RQ-4A Global Hawk unmanned surveillance drone. A drone of this model was shot down by Iran on Thursday 21 June AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures An oil tanker is on fire after it was subject to a suspected attacked at the Gulf of Oman on June 13. The US has blamed Iran for the attack Reuters Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, debris from the downed US drone is seen after it was recovered from Iranian waters AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures US President Trump holds up a signed executive order to increase sanctions on Iran on 24 June AP Tensions high as Trump approves new Iran sanctions: In pictures Iranian President Rouhani stated in a televised address that the White House is "afflicted by mental retardation" following the increase in sanctions on 25 June EPA Tensions high as Trump approves new Iran sanctions: In pictures An Iranian navy boat tackles the fire on the Norwegian owned Front Altair oil tanker after it was hit in a suspected attack AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, debris from the downed US drone is seen after it was recovered from Iranian waters AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures A screenshot from a video released by the US Department of Defense that the US claims to show Iranian removing an unexploded limpet mine form the hull of the Japan-owned ship that was attacked in the Gulf of Oman on June 13 Getty Tensions high as Trump approves new Iran sanctions: In pictures An item reportedly found on the Japan-owned oil tanker that was attacked on June 13 in the Gulf of Oman AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures A handout photograph from the US Department of Defense shows a composite material that the US claim was left behind on the hull of the Japan-owned oil tanker following the removal of an unexploded limpet mine Getty Tensions high as Trump approves new Iran sanctions: In pictures A view from the cabin of an Iranian navy boat as it tackles the fire on the Norwegian owned Front Altair oil tanker after it was hit in a suspected attack EPA Tensions high as Trump approves new Iran sanctions: In pictures Release by US government A picture released by U.S. Central Command shows damage to the hull of the oil tanker Kokuka Courageous. The picture suggests that the ship is 'likely' to have been hit by a mine as the US Secretary of State Mike Pompeo moves to blame Iran for the suspected attack Reuters Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures Release by US government A picture released by U.S. Central Command shows damage to the hull of the oil tanker Kokuka Courageous. The pictures suggests that the ship is 'likely' to have been hit by a mine as the US Secretary of State Mike Pompeo moves to blame Iran for the suspected attack EPA

Here is a timeline of recent incidents involving the three nations:

13 June: Two US oil tankers near the Strait of Hormuz were attacked in an assault that left one ablaze and adrift, with 44 sailors evacuated from both vessels. The US Navy went to assist, with Mr Trump blaming Iran for the incidents.

Iran denied involvement in the tanker attacks and accused the US of promoting an "Iranophobic" campaign.20.

20 June: A US military drone worth $100m (£78m) was downed by Tehran, with Iran's president Hassan Rouhani claiming it had violated their airspace.

The move marked a new high in the rising tensions between the two countries, as Iran's naval commander warned his forces would not hesitate to down more US drones if they entered its airspace.

Mr Trump then pulled back from the brink of retaliatory military strikes on Iran after he was told 150 people could die.

He has since signed an executive order targeting Iran's supreme leader Ali Khamenei and his associates with financial sanctions.

4 July: Royal Marines from 42 Commando were involved in an operation to seize a supertanker off Gibraltar suspected of carrying oil destined for Bashar Assad's Syrian regime. They boarded the ship by descending on ropes from a Wildcat helicopter and by using rigid inflatable boats.

They worked alongside authorities in Gibraltar to detain the Iranian tanker Grace 1, which was believed to be heading to the Banyas refinery in breach of EU sanctions. In response, Iran's revolutionary guard warned a British oil tanker could be seized in retaliation.

10 July: Royal Navy frigate HMS Montrose drove off three Iranian vessels which tried to stop the commercial ship British Heritage.

It is understood the tanker was making passage out of the Gulf through the Strait of Hormuz when the ship was approached by the Iranian vessels. HMS Montrose was nearby and proceeded to come in between.

Warnings were given but no shots were fired. The Iranian vessels then turned around and left.

11 July: Police in Gibraltar said they had arrested the captain and chief officer of the Iranian supertanker Grace 1 in relation to suspected violations of EU sanctions on Syria.

Two days later the force said the captain, chief officer and two second officers of the vessel had been conditionally bailed without charge.

13 July: In a telephone call with Iranian foreign minister Mohammad Javad Zarif, Foreign Secretary Jeremy Hunt offered to facilitate Grace 1's release in return for guarantees from Tehran that it would not breach EU sanctions on the Assad regime in Syria.

15 July: Mr Hunt attended a Brussels meeting of EU foreign ministers on the issue of the Iran nuclear deal. He said there was a "small window" of hope for preventing the international agreement, aimed at stopping Tehran gaining nuclear weapons, from unravelling.

Both he and Tory leadership rival Boris Johnson later ruled out supporting Mr Trump should he pursue military action in the Gulf.

16 July: Ali Khamenei called the seizure of the Grace 1 tanker "piracy" and vowed to retaliate. He said: "God willing, the Islamic Republic and its committed forces will not leave this evilness without a response."

Donald Trump says Iran is 'Nothing but trouble'

17 July: US officials said they suspected Iran had seized a Panamanian-flagged oil tanker from the United Arab Emirates as it travelled through the Strait of Hormuz. The tanker had turned off its tracker three days before as it entered Iranian waters.

Iran later said its Revolutionary Guard had seized a foreign oil tanker and its crew of 12 for smuggling fuel out of the country.

18 July: Mr Trump said the USS Boxer had shot down an Iranian drone that came within 1,000 yards of the warship and ignored calls to stand down.

Iranian military officials denied one of its drones had been lost in the Strait of Hormuz.

19 July: Two oil tankers are reported to have been seized by Iranian authorities in the Persian Gulf.

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The Stena Impero, registered in the UK, was seized by the Iranian Revolutionary Guard in the Strait of Hormuz for "violating international maritime rules", the semi-official Fars news agency said.

A second oil tanker, the Liberia-flagged Mesdar, owned and operated by Glasgow-based firm Norbulk, appeared to veer off course towards the Iranian coast.

The Mesdar's operator said the ship was boarded by armed guards but the crew were left "safe and well" and allowed to continue their voyage.

Jeremy Hunt called the ships' seizure "unacceptable" ahead of attending a meeting of the Government's emergency committee Cobra.