Torrential monsoon rains and floodwaters swept a crowded bus off a bridge into a shallow ravine in eastern Pakistan Friday and up to 71 people were killed, police said.

They said nine people survived and 18 bodies were recovered.The disaster occurred Thursday in eastern Punjab province, about 20 miles southeast of Islamabad. Police said the bus was so crowded, passengers were riding on the roof.

The police chief of the nearby village of Kahuta, Riaz Hussain Shah, said the bus became trapped in floodwaters as it crossed the bridge and was swept away by the current.