US Secretary of State Mike Pompeo said Washington had asked more than 60 countries to help secure shipping lines and welcomed Britain's response to the US initiative.

The US secretary of state described Iran as "the world's largest state sponsor of terrorism, showed willingness to pull commercial ships out of the sea, laid mines on six ships, pulled a British ship out of the water and still holds it."

"We want to make sure that we have a comprehensive program that prevents Iran from doing anything that could ignite a conflict in the region, which the United States certainly does not want," said Pompeo, who is currently visiting Australia.

He stressed that the best way to do this is deterrence to create stability, so we asked more than sixty countries to provide assistance in securing shipping lines in the Strait of Hormuz, so that all ships to walk safely, as he put it.

The Department of Defense welcomed the participation of Britain in the protection of waterways in the Gulf and the Arabian Sea and the Strait of Hormuz and Bab al-Mandeb.

British Defense Secretary Ben Wallace said on Monday that his country would join a US-led naval security mission in the Gulf to protect merchant ships crossing the Straits of Hormuz, saying London looked forward to working with Washington and others to find an international solution to problems in the Straits.

Washington is finding it difficult to form a coalition to carry out the task. A German government spokeswoman said her country was not currently contemplating taking part in a US-led naval mission in the Strait of Hormuz.

Iran rejects the presence of foreign forces in the waters of the Gulf, and stresses that ensuring the security of the Gulf waters is the responsibility of the surrounding countries in accordance with international decisions and laws.

Tensions have risen in recent months between Washington and Tehran after a unilateral US withdrawal from the nuclear treaty signed in 2015, the re-imposition of sanctions on Tehran, and the United States imposed sanctions on Iranian Foreign Minister Mohammad Jawad Zarif.

The dispute has spread to the Strait of Hormuz in recent weeks, where Iran last month detained a British-flagged oil tanker after Britain seized an Iranian oil tanker off the Gibraltar colony on suspicion of violating EU sanctions.