A Turkish policeman has died after he sustained serious wounds when a female suicide bomber blew herself up, according to Turkish media.

The female assailant was said to have entered the police station in the Sultanahmet district, detonating the explosives she was carrying on her at about 5 p.m. local time (15:00 GMT).

Istanbul governor Vasip Sahin told Turkish television that the woman had spoken English to officers manning a post to help tourists near to the Aga Sophia museum and Blue Mosque. Emergency services were quickly called to the scene and a local tram line halted.

Officials said there was no clue as yet as to the nationality or identity of the bomber, who died in the attack.

"She approached the police… saying in English: 'I have lost my wallet.' That's all I can say," Sahin said. "We are trying to identify the attacker."

Police discovered that not all of the explosive charges on the body of the woman had detonated. Those that remained were detonated in a controlled explosion.

The attack on police is the second in a week. Five days earlier, police subdued a man who had thrown hand grenades and fired a weapon at officers on guard duty at the Ottoman-era Dolmbahce Palace.

Both grenades hurled by the man, named as Firat Ozcelik, failed to explode. That attack was claimed by the Revolutionary People's Liberation Party-Front, a group that espouses a Marxist-Leninist ideology.

rc/sgb (AFP, AP, dpa, Reuters)