TEHRAN  Tehran’s police chief, who was responsible for a crackdown on immodestly dressed women for the past year, has been arrested, a spokesman for the judiciary confirmed Tuesday.

At a news conference, the spokesman, Alireza Jamshidi, would not give the reason for the arrest, the semiofficial Fars news agency reported.

Web sites and local newspapers reported last month that the chief, Gen. Reza Zarei, had been arrested after being caught in a police raid at an underground brothel with six naked prostitutes.

The announcement on Tuesday was the first official confirmation of the arrest.

The chief led a crackdown that started a year ago to increase enforcement of Islamic regulations. Thousands of young women were detained for violating the Islamic dress code, usually for wearing head scarves that showed too much hair, coats that were tight enough to reveal the figure or pants that were too short. Prostitution is illegal in Iran and can be punished severely.