Tehran, Iran ? A fire raged through a crowded mosque in Tehran during evening prayers Monday after a female worshipper’s veil caught the flames of a kerosene heater, killing at least 59 people and injuring more than 250, Iran’s official news agency reported.

The Arg Mosque was filled with about 400 worshippers, more crowded than usual because this is the Islamic month of Muharram, a holy period for Shiite Muslims.

Panicked people raced for the doors and smashed windows to escape the blaze, leaving burned shoes and women’s black chadors scattered in the mosque yard. The mosque walls were charred, carpets were burned, and religious books, including the Quran, were destroyed.

Women, who pray on the second floor of the mosque, separated from the men, had to race down stairs and through a narrow doorway to exit. Many stumbled and were trampled in the frenzied stampede to escape.

Hospital records checked by The Associated Press showed that 40 of those killed and the majority of the injured were women.

Tehran Police Chief Brig. Gen. Morteza Talaie was quoted by the Islamic Republic News Agency as saying 59 people were confirmed killed. More than 250 people were injured in the fire, according to rescue workers.

The fire started when the veil of a female worshipper caught the flames of a kerosene heater on the upper floor of the mosque. The flames spread to a thick green cloth that covered the ceiling and walls of the mosque in commemoration of the holy month.

Earlier reports had blamed a faulty electrical outlet, but IRNA reported that theory had been discarded. It also said officials had discounted the possibility of a bomb or arson attack.

The injured, some of them in critical condition, were taken to nearby hospitals. Relatives gathered outside to await news of their loved ones.

Workers clean the yard of the mosque where a fire broke out Monday that killed at least 35 worshippers in central Tehran, Iran.

“My brother has been seriously injured. What a calamity,” said Masoumeh Ebrahimi, wiping her tears with a corner of her chador, a head-to-toe covering.

Firefighters extinguished the fire an hour after it started, state television said.

But Reza Pourbaradaran, who lives nearby, complained that firefighters arrived too late.

“Firefighters arrived one hour after the fire broke and when serious damage had been done,” he said.

Workers were seen late in the evening cleaning the debris and wiping away the black smoke marks from the entrance.

The tragedy came on the fourth day of the month of Muharram, a period of mourning for Shiites, when they recall the seventh century death of Hussein, grandson of Islam’s prophet Muhammad.

The mosque is close to the historic Golestan Palace where Reza Khan was crowned as Reza Shah Pahlavi in the 1920s and the huge Tehran bazaar, the heart of business in the capital.