An independent assessment by Britain has concluded that Iran was "almost certainly" responsible for the latest Gulf tanker attacks, British Foreign Secretary Jeremy Hunt said Friday.

"Our own assessment leads us to conclude that responsibility for the attacks almost certainly lies with Iran. These latest attacks build on a pattern of destabilising Iranian behaviour and pose a serious danger to the region," Hunt said in a statement.

The foreign office statement pinned the blame for Thursday's attack on the Islamic Revolutionary Guard - a vast and powerful branch of the Iranian military.

"No other state or non-state actor could plausibly have been responsible," the foreign office statement said.

Hunt called on Iran to "cease all forms of destabilising activity" and said Britain was working with other countries to try to find a diplomatic solution to the escalating standoff between Tehran and Washington.

Iran rejects the accusation of staging the Gulf of Oman attacks.