(AFP) — Britain’s ambassador to Iran on Sunday denied he was summoned by the Iranian foreign ministry after London accused Tehran of “almost certainly” being responsible for tanker attacks in the Gulf.

“Interesting. And news to me,” ambassador Rob Macaire said in a tweet a day after the Iranian foreign ministry said in a statement that it had summoned the envoy over his government’s accusations.

“I asked for an urgent meeting with the Foreign Ministry yesterday and it was granted. No ‘summons’. Of course if formally summoned I would always respond, as would all Ambassadors,” Macaire wrote.

Iran’s foreign ministry said the head of its European affairs Mahmoud Barimani met Macaire on Saturday and “strongly protested against the unacceptable and anti-Iranian positions of the British government”.

On Friday, British Foreign Secretary Jeremy Hunt said London had concluded Iran was “almost certainly” responsible for Thursday’s tanker attacks.

He was echoing remarks by US President Donald Trump who said Thursday’s attacks on two tankers in the Gulf of Oman had Iran “written all over it”.

Iran has denied any involvement in the twin attacks.

It dismissed Hunt’s accusations as “false” and chided London for its “blind and precipitous alignment” with US views, according to the foreign ministry.

The latest incident comes as ties between Tehran and London have been strained in recent months, namely over the fate of a British-Iranian mother jailed in Iran on sedition charges.

London has repeatedly called for the release of Nazanin Zaghari-Ratcliffe, who was arrested in April 2016 as she was leaving Iran after taking their infant daughter to visit her family.

Zaghari-Ratcliffe, who is serving a five-year sentence for allegedly trying to topple the Iranian government, has begun a hunger strike in protest at her detention, her husband said on Saturday.

She previously went on hunger strike in January.

Richard Ratcliffe urged the Iranian authorities to immediately release his wife and to allow the British embassy to check on her health, and also asked they grant him a visa to visit her.

On Saturday he also stood outside Iran’s London embassy and said he would maintain his own hunger strike and vigil for as long as his wife refused food.