The United Kingdom is increasing its military presence in the Persian Gulf, amid escalating tensions with Iran.
The British military announced Friday that it is deploying a second warship to the region after the UK warned that the risk on British shipping in the waterway had reached a "critical" level.
Iranian vessels harassed British oil tankers Wednesday, the British Ministry of Defence said. The Iranian boats attempted to block tankers from travelling in the Gulf before being driven off by a British warship.
Earlier this week, UK forces seized an Iranian tanker in Gibraltar which had been bound for Syria.