LUCKNOW: An overloaded bus carrying pilgrims to a Muslim shrine rammed into a parked truck and burst into flames overnight, killing 16 and injuring more than two dozen in the north Indian state of Uttar Pradesh, police said Saturday.

Some of the 78 passengers aboard the 54-seater bus had kerosene and cooking gas cylinders that helped to turn the bus ''into a ball of fire,'' Officer Iqbal Mallik said.

Some passengers escaped through the back door of the bus and others through a window. Those injured with burns, including nine in serious condition, are being treated at a nearby state hospital.

The bus operators are being investigated for illegally allowing flammable cooking items aboard instead of preparing food themselves, as is customary on Indian tours, State Labour Minister Waqar Ahmad said.

''The permit of the tour operator has been cancelled,'' Ahmad said.

The pilgrims from three villages in Sultanpur district were travelling to a shrine in Ajmer when the accident took place in Bahraich, about 130 kilometres southeast of Lucknow.

Ajmer holds the tomb of Moinuddin Chishti, a Sufi teacher who in the 13th century helped establish a religious order that is prevalent in India and Pakistan.

Bus accidents due to reckless driving, bad roads and poorly maintained vehicles are common in India.