Baghdad: A suicide truck bomb exploded on a major bridge in Baghdad early on Thursday, collapsing the steel structure and sending cars toppling into the Tigris River below, police and witnesses said.

At least 10 people were killed and 26 injured, according to hospital officials. That toll was expected to rise.

The truck bomb occurred during the morning rush jour and damaged the Sarafiya bridge in northern Baghdad, destroying parts of the steel structure.

Four or five cars fell into the river. Police are reportedly looking for survivors in the waters.

Checkpoints are placed at the entrances to most of the many bridges that cross the Tigris in Baghdad. US and Iraqi forces launched a security crackdown in the capital two months ago.