Two tankers were last week damaged by explosions in the Gulf of Oman. The US has blamed Iran, amid continued tensions between the nations.
Iran denies involvement in the incident, which saw explosions on two ships while sailing in international waters through the Gulf of Oman, a key shipping channel.
The crews escaped unharmed, but the vessels were severely damages, and there is concern that oil may have spilled into the water.
Asking an urgent question in the Commons, Jo Swinson asked the Government to make a statement.
Responding for the Government, the Minister of State for the Middle East at the Foreign & Commonwealth Office, Dr Andrew Murrison said;
"Following our own assessment, the UK concludes that it is almost certain that a branch of the Iranian Military, the Islamic Revolutionary Guard Corps attacked the two tankers on 13 June. No other state or non-state actor could plausibly have been responsible."
He said that he had met with the Iranian Ambassador and would go to Tehran, expressing that the UK wished to strongly urge de-escalation of tensions in the region.
Jo Swinson thanked the Minister for the statement, urged caution in the ongoing investigation and raised concerns about the adverse effect of escalation on peace in the region and on British nationals, including Nazanin Zaghari-Ratcliffe, who remains incarcerated in Iran.
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