The UK has brought forward plans to send a second warship to the Gulf amid rising tensions with Iran.

HMS Duncan is currently in the Mediterranean and is expected to join HMS Montrose in the region next week. It comes after the UK government said Iranian boats tried to impede a British oil tanker in the Gulf on Wednesday.

Meanwhile, Iran has reiterated calls for the UK to release an Iranian-owned oil tanker that was detained by Royal Marines in Gibraltar last week.

An Iranian official, speaking to state news agency IRNA, warned the UK not to get involved in “this dangerous game”.

The relationship between the UK and Iran has become increasingly strained in recent weeks.

On Tuesday, the UK raised the threat to British shipping in Iranian waters in the Gulf to the highest level – where the risk of attack is critical.

The following day, boats believed to belong to Iran’s Islamic Revolution Guard Corps (IRGC) approached the British Heritage tanker and tried to bring it to a halt as it was moving out of the Gulf into the Strait of Hormuz.

HMS Montrose, a British frigate shadowing the BP-owned tanker, was forced to move between the three boats and the ship, a Ministry of Defence spokesman said. Iran denied any attempted seizure.

HMS Duncan, a type 45 Destroyer, will operate alongside HMS Montrose in the Gulf for a short period, before HMS Montrose goes back to Bahrain for routine maintenance.

A government spokeswoman said: “As part of our long-standing presence in the Gulf, HMS Duncan is deploying to the region to ensure we maintain a continuous maritime security presence while HMS Montrose comes off task for pre-planned maintenance and crew changeover. “This will ensure that the UK, alongside international partners, can continue to support freedom of navigation for vessels transiting through this vital shipping lane.”

Foreign Secretary and Tory leadership candidate Jeremy Hunt – who earlier said events in the Gulf showed the Royal Navy needs more warships – told the BBC the UK wanted to “de-escalate the situation” but had “a responsibility to protect British shipping”.