TONGI, Bangladesh (AP) _ A tornado tore a gathering of thousands of Islamic preachers, catching the clerics by surprise at evening prayer. At least 25 people died, and another 5,000 were injured, rescue workers said today.

The tornado stayed on the ground for a full half-hour Sunday, devastating a three-square-mile area. The twister blew away tin roofs, trees and electricity poles near Tongi, an industrial town 10 miles north of Dhaka, the capital city.

The government confirmed 15 dead and at least 1,000 injured. Rescue workers put the toll higher.

Hospitals in Dhaka and Tongi said at least 500 people were admitted for treatment of injuries. Many others received first aid at private clinics.

Most of the dead were killed by flying debris, survivors said.

``Tin was flying like pieces of paper tossed into the air,'' said Baker Ali, a preacher who survived the tornado.

Torn pieces of metal, iron rods, wood, cooking utensils, shoes and water pots littered the muddy field where the Islamic clerics had gathered.

The preachers were elderly members of the World Congregation of Muslim Devotees and had gathered on the banks of the Turag River for a five-day seminar to study Islam.

``We first saw a thick black cloud in the northern sky. It was hot and humid. But we thought it was going to be the usual pre-winter rains,'' said Mohammad Ali, 60, who spoke as a nurse bandaged his leg at a Tongi hospital.

Many of the devotees returned home immediately after the disaster.