Hundreds of women have been reportedly arrested since April

Tehran police chief Ahmad Reza Radan said from 23 July twice as many police will tackle "immoral behaviour".

Hundreds of women have already been arrested and some beaten by police since the drive began in April, human rights groups say.

Iranian women are obliged to cover their hair and wear loose-fitting clothes to disguise their figures.

However, some women - especially in wealthier urban areas - wear tighter or more revealing clothes.

Court warning

Ahmad Reza Radan told Iran's Farhang-e Ashti newspaper that police would be enforcing the crackdown with renewed vigour in Mordad - the Iranian month starting on 23 July.

Men also are subject to scrutiny over their clothing

"First, those who breach the dress code will be warned by the police.

"But if they continue their ignorance... they will be sent to courts," Mr Radan said.