The British minister for the Middle East had "open, frank and constructive" talks with Iranian government representatives about rising tensions in the region during a visit to Tehran, Britain's Foreign and Commonwealth Office said on Sunday.
"I reiterated the UK's assessment that Iran almost certainly bears responsibility for recent attacks on tankers in the Gulf of Oman," Andrew Murrison, minister for the Middle East and North Africa, said in a statement.
"Such activity, which carries a high risk of miscalculation, needs to stop to allow for immediate de-escalation of rising tensions." Tehran has denied involvement in the tanker attacks.
US President Donald Trump said on Sunday he was not seeking war with Tehran after a senior Iranian military commander warned any conflict in the Gulf region could spread uncontrollably and threaten the lives of US troops.
Murrison said he reiterated Britain's determination to maintain the nuclear deal Iran signed with world powers in 2015 during his talks with government representatives, including Vice President Masoumeh Ebtekar, Deputy Foreign Minister Abbas Araghchi and the Deputy Head of the Atomic Energy Organisation of Iran Behrouz Kamalvandi.
Tehran said in May it would reduce compliance with the pact in protest at the U.S. decision to unilaterally pull out of the agreement and reimpose sanctions last year.
"I was clear that Iran must continue to meet its commitments under the deal in full – including the limits imposed on its low-enriched uranium stockpile," Murrison said.
Murrison said he had also pressed again on behalf of the British government for the "urgent and unconditional release" of British-Iranian aid worker Nazanin Zaghari-Ratcliffe.
Zaghari-Ratcliffe, a project manager with the Thomson Reuters Foundation, was arrested in April 2016 at a Tehran airport as she headed back to Britain with her daughter after a family visit.
She was sentenced to five years in jail after being convicted of plotting to overthrow Iran's clerical establishment, a charge denied by her family and the Foundation, a charity organization that operates independently of Thomson Reuters and Reuters News.