Another potential escalation between Iran and the western powers appeared to have been averted amid claims by US and UK officials on Thursday that three ships belonging to Iran’s Revolutionary Guards sought “attempted to impede” a British oil tanker in the Strait of Hormuz.

Iranian officials bluntly denied any such incident took place.

Wednesday’s alleged incident in the Gulf follows the 4 July seizure of an Iranian-linked oil-tanker Grace I by UK forces off the coast Gibraltar on suspicions it was carrying crude oil to an embargoed refinery in Syria. It happened on the same day the US demanded that world powers punish Iran for upping its enrichment of uranium.

Tehran has warned for days that Britain would face “repercussions” – but, adding to the confusion, Iranian officials on Thursday denied the Panamanian-flagged ship was owned by Iran, with a military commander claiming it was only leased by Tehran.

“We had rented this ship and it was carrying the cargo,” Rear Admiral Ali Fadavi, deputy commander of the Revolutionary Guard, was quoted as saying by the Tasnim news agency. “Their action was very silly and they will certainly regret it.”

The incident threatens to further increase strains between western powers and Iran as they seek to salvage a 2015 nuclear deal after the US pulled out and announced harsh sanctions on Tehran.

The UK claimed Revolutionary Guard vessels approached the BP-owned British Heritage in the Gulf on Wednesday, asking it to stop in nearby Iranian waters, but withdrew after a Royal Navy warship issued them “verbal warnings” over radio.

US defence personnel said the navy frigate HMS Montrose, which was accompanying the tanker, “pointed its guns at the [Iranian] boats”, according to US media reports. The Ministry of Defence had no immediate comment when contacted by The Independent.

“It was harassment and an attempt to interfere with the passage,” one of the US officials reportedly said, speaking on the condition of anonymity.

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

The British government statement said: “We are concerned by this action and continue to urge the Iranian authorities to de-escalate the situation in the region.”

But Iranian foreign minister Mohammad Javad Zarif and the Revolutionary Guard’s navy both denied any incident had taken place involving the British Heritage. “During the last 24 hours, there were no encounters with foreign vessels, including the British Tides,” said a statement by Revolutionary Guard naval forces cited by the Fars news agency.

No audio or video recordings of the incident have yet emerged.

It remains unclear whether the conflicting accounts were the result of a misinterpretation or misleading statements. Iranian boats in the Gulf have for years harassed US and other ships moving out of the waterway, drawing too close in what American officials often dismissed as annoyances.

Hours before the incident Iran’s president, Hassan Rouhani, had referred to the UK tanker, noting that the UK had “to bring your frigates [to escort it] because you are scared.”

“Why do you commit such acts?” he said. “You should instead allow navigation to be safe.”

On Thursday, Mr Zarif rejected the claims that Iran had sought to seize the ship. “They make such claims to create tension, yet these claims are worthless and they have made many such claims,” he told reporters, according to the semi-official ISNA news agency. “They say such things to cover up their own weaknesses.”

Russia, which has increasingly asserted itself in the Middle East as a broker and spoiler, called for restraint and “unconditional” freedom of navigation following the incident, but refused to endorse either the UK or Iranian version of events. President Vladimir Putin’s spokesman, Dmitry Peskov, was quoted as saying by the Interfax news agency the Kremlin had “registered the information that such an incident has allegedly taken place, and we have also registered the statement by Iranian representatives that this information does not correspond to reality”.

Asked whether the UK planned to step up its military presence in the region to enhance protection to shipping, a Downing Street spokesman said: “We have a long-standing maritime presence in the Gulf. We are continuously monitoring the security situation there and are committed to maintaining freedom of navigation in accordance with international law.”

Pressed on whether the UK saw Wednesday’s incident as a response to the seizure of Grace I, the spokesman said: “I’m not going to speculate on Iran’s motivations. Our position from last week stands. We’ve been very clear that Grace I is a Syria sanctions issue, rather than an Iran issue.”

Media reports suggested that British-flagged ships in the Strait of Hormuz had now been put on “heightened security” following new guidance from the Department for Transport.

A spokesperson from the department told The Independent that they were unable to comment on the reports.

The alleged confrontation in the Gulf took place as the US reportedly demanded at a closed-door meeting of the International Atomic Energy Agency (IAEA) in Vienna that the world take action against Iran for breaching its commitments under the nuclear deal, even as Washington itself had withdrawn from the agreement at the behest of Beltway Iran hawks, Israel, and Gulf Arab monarchs.

According to statements by Iranian and Russian officials, US officials failed to gain traction at the IAEA as much of the world remains committed to upholding it despite relatively minor breaches by Iran that Tehran describes as responses for the failure to remove impediments to trade with the Islamic Republic.

Tehran has offered to return to the agreement, but the US president has rejected the deal, arguing it was too generous to Iran and did not address its involvement in regional conflicts.

In May, the US dispatched an aircraft carrier, bombers and fighter jets to the Gulf in response to alleged Iranian threats.

The US has also accused Iran of being involved in the bombing of oil tankers in the Gulf and said it shot down an American drone in international airspace.