British warship HMS Kent set sail for the Gulf on Monday to join a U.S.-led mission protecting commercial shipping vessels in the region amid heightened political tension between the West and Iran.

Britain has joined the United States in a maritime security mission in the Gulf to protect merchant vessels.

That comes after Iran seized a British oil tanker in the Strait of Hormuz. On July 4 British marines seized an Iranian vessel, which is suspected of smuggling oil to Syria, off the coast of Gibraltar.

“Our focus in the Gulf remains firmly one of de-escalating the current tensions,” said Andy Brown, the ship’s commanding officer.

“But we are committed to upholding freedom of navigation and reassuring international shipping, which this deployment on operations aims to do.”

The deployment was first announced last month and will see the Kent relieve another British ship, the Duncan, already working in the region.