Iran's leaders have sent their condolences to the grieving families of the victims of a mosque fire that killed 59 worshippers in Tehran Monday.

Supreme Leader Ayatollah Ali Khamenei and President Mohammad Khatami issued separate statements  Tuesday promising the best possible medical care for the more than 200 injured, and an investigation into the fire's cause.

No official cause has been determined, but initial reports point to a kerosene heater that ignited either a curtain or a woman's veil, setting the Arg mosque on fire.

The fire broke out during evening prayers in the women's section of the mosque. Witnesses said the flames spread quickly, and dozens of worshippers were killed or injured from a stampede triggered by panic.

Some information for this report provided by AP and AFP.