Britain says it is joining the United States in an "international maritime security mission" to protect merchant vessels traveling through the Strait of Hormuz, a key shipping line that connects the Persian Gulf and the Arabian Sea.
"The U.K. is determined to ensure her shipping is protected from unlawful threats," Defense Minister Ben Wallace told reporters on August 5.
"We look forward to working alongside the U.S. and others to find an international solution to the problems in the Strait of Hormuz," Wallace said.
Royal Navy vessels will work alongside the U.S. Navy to escort ships through the busy strait, according to the Defense Ministry.
The move comes amid rising tensions between London and Tehran.
In recent weeks, Iran and Britain have seized a tanker each, and London has sent two warships to the Gulf to shadow British vessels in the area.
The United States has been asking its allies to take part in a naval mission to protect shipping in the Strait of Hormuz, though European nations have been reluctant.
The U.S. Defense Department welcomed the British decision.
"This is an international challenge and we look forward to the opportunity to work together with the Royal Navy and with additional partners and allies who share the common goal of ensuring the free flow of commerce," a Pentagon spokeswoman said in a statement.
Germany has made clear that it would not participate in a mission led by the United States and said on August 5 it was pushing for a European Union observer mission to protect shipping in the Gulf.
But German Foreign Minister Heiko Maas said that it will “certainly take some time to convince the EU of this."
In Tehran, Iranian Foreign Minister Mohammad Javad Zarif told a news conference that U.S. allies are too "ashamed" to join its forces in the Gulf, amid Washington's campaign of maximum pressure on Iran that includes the U.S. withdrawal from the 2015 nuclear deal last year and the reimposition of crippling sanctions.
"Today the United States is alone in the world and cannot create a coalition. Countries that are its friends are too ashamed of being in a coalition with them," Zarif said.
In July, Iran seized a British-flagged tanker in the Strait of Hormuz for alleged violation of maritime laws, following the impounding of an Iranian tanker off Gibraltar.
London said the Iranian vessel was suspected of breaching EU sanctions against Syria. Iran denied it was headed to that country.
Britain has already positioned two warships in the Persian Gulf -- the frigate HMS Montrose and the destroyer HMS Duncan – to accompany U.K.-flagged vessels through the Strait of Hormuz.
The United States has also boosted its military presence in the region after two separate attacks using explosives that damaged oil tankers in the Gulf of Oman earlier this year.
Washington has blamed Tehran for the attacks. Iran denied any involvement.