Iran has shot down a US military drone using a surface-to-air missile, Iranian and American military officials said, amid an escalating row over alleged attacks on oil tankers in the Strait of Hormuz.

The commander of the Revolutionary Guard said the downing of the drone had sent ”a clear message” to America. In a speech delivered on state television, General Hossein Salami added that Iran does “not have any intention for war with any country, but we are ready for war.”

The two sides differed in their accounts of where it was at the time. The US military described the incident as ”an unprovoked attack on a US surveillance asset in international airspace”, while Iran’s Revolutionary Guard said it had entered Iranian territory near the Kouhmobarak district in the south of the country.

Two Iranian state media outlets carried statements that referred to a “spy” drone being destroyed on Thursday morning. The US military, which initially declined to confirm reports of a downed drone, later said that an “RQ-4A Global Hawk” unmanned aircraft was hit by a surface-to-air- missile at 11.35pm on Wednesday evening.

Tensions have remained high between the two countries since US president Donald Trump withdrew from an international nuclear deal with Iran, which granted it sanctions relief in exchange for tight controls on the state’s nuclear programme.

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

But the Strait of Hormuz, a key shipping lane in the Gulf of Oman close to where Iran says the drone was shot down, has been a more immediate flashpoint in recent weeks amid a spate of attacks on oil tankers.

The US and its ally Saudi Arabia have blamed Iran for the incidents, and the US has deployed an aircraft carrier to the Middle East and additional troops to add to the tens of thousands already in the region.

Iran has denied involvement but said that security for the Strait of Hormuz was its responsibility, demanding American forces be withdrawn.

Trump withdrew from the landmark nuclear deal in May last year, ending the US commitment to an agreement signed by his predecessor Barack Obama, along with Russia, Britain, Germany, China and the European Union. Trump called the deal “defective to its core,” contradicting US allies who insisted it was successful.

The terms of the agreement limited the amount of low-enriched uranium stockpiled by Iran, which is a necessary component of a nuclear weapons programme.

The US has imposed several rounds of punishing sanctions on Iran over the past year, aimed at pressuring its leadership to accept terms more favourable to the US.

But this week, Iran’s nuclear agency announced that it would increase enrichment of uranium to surpass the caps agreed upon in 2015.

“We have quadrupled the rate of enrichment (of uranium) and even increased it more recently, so that in 10 days it will bypass the 300kg limit,” said Iran’s Atomic Energy Organisation spokesperson Behrouz Kamalvand.

“Iran’s reserves are every day increasing at a more rapid rate,” he told state TV, adding: “The move will be reversed once other parties fulfil their commitments.”

The US responded by calling for Iran to honour the agreement which Trump had withdrawn from.