Deputy Head of the British Mission in Tehran Kate Smith went to the Foreign Ministry in place of the British ambassador, who was away, to receive an official complaint over the illegal entry of British naval personnel into Iranian waters, state television reported.
Smith met with the director-general of Western European Affairs at the Foreign Ministry, Ibrahim Rahim-Pour, who demanded that the British government promptly explain the illegal intrusion.
Britains Ministry of Defence (MoD) announced on Friday that 15 of its sailors and marines had been seized by Iranian military forces in the Persian Gulf.
The incident took place at approximately 10:30 Iraqi time, a statement said.
The British personnel were engaged in routine boarding operations of merchant shipping in Iraqi territorial waters in support of United Nations Security Council Resolution 1723 and the government of Iraq.
Operating from HMS Cornwall, the UK boarding party had completed a successful inspection of a merchant ship when they and their two boats were surrounded and escorted by Iranian vessels into Iranian territorial waters.
The British Government is demanding the immediate and safe return of our people and equipment, the statement added.
In London, the Permanent Under-Secretary in Britains Foreign Office Peter Ricketts summoned Rasoul Movahedian to protest the seizure.
