Iran's state TV says British Foreign Secretary Philip Hammond has reopened the British Embassy in Tehran nearly four years after it was closed following an attack by hardliners.

Hammond arrived in Tehran on Sunday to attend the reopening ceremony and for talks with Iranian officials. It's the first visit by a British foreign secretary to Iran since 2003.

Iran's Deputy Foreign Minister Majid Takht-e-Ravanchi told state television Saturday that the Iranian Embassy in London will reopen at the same time. He said the two embassies will operate at the charge d'affaires level.

The British Embassy has been closed since hard-liners protesting the imposition of international sanctions stormed it in November 2011.

The recent nuclear deal between Iran and world powers helped accelerate a thaw in relations between Britain and Iran.