Suspected militants bombed the mausoleum in Pakistan of a 17th-century poet on Thursday, apparently because women have been visiting the shrine.

A letter delivered to the management of the mausoleum of Abdul Rehman, commonly known as Rehman Baba, on the outskirts of Peshawar in northwestern Pakistan three days before the attack warned against "shrine culture," Sahibzada Mohammad Anees, a top government official in the city told Pakistan's English-language DawnNews television.

The letter also noted that women were coming to pray at the shrine.

No one was hurt in the pre-dawn blast but the mausoleum was badly damaged.

The Sufi poet is revered in Pakistan and Afghanistan for his mystical, melodic poetry. Written in the Pashto language, his verses about love and peace are commonly quoted and have been translated into English, French, Russian, Urdu, Arabic and other languages. A professor at Peshawar University told the television network that Rehman Baba's poems are kept alongside the Islamic holy book, the Quran, in many homes.

Islamic militants have been stepping up attacks in Pakistan, especially in the Pashtun-dominated northwest, and are increasingly seen as a threat to the nation of 170 million people.

They have tried to stamp out what they see as inappropriate practices such music and dancing. They also consider paying homage at graves heretical. And they believe Islam prohibits men and women from mingling unless they are husband and wife.