KARACHI - A passenger train collided with a cargo train on the edge of Pakistan's biggest city Karachi, killing at least 12 people on Tuesday and injuring more than 30 others, officials said.

"So far we have recovered the bodies of 12 passengers and rescued 38 injured people and sent them to hospitals," Muzaffar Shaikh, a senior railway police official, told AFP.

He said the operation was not over and there were still some bodies and injured passengers trapped inside one of the carriages.

"My officials have seen a couple more bodies and are trying to take them out," Shaikh said.

"We are also hearing the cries of a child and are trying to locate him," he added,

Hospital officials said they were receiving the bodies and injured people from the incident.

"We have received 10 bodies so far and more than 30 injured passengers," doctor Seemi Jamali of Jinnah Hospital told AFP.

The accident took place at Juma Goth, in the suburbs of Karachi, when the driver of the Karachi-bound Allama Iqbal express ignored a traffic signal and collided with the goods train, senior railway official Aftab Memon said.

Most of the casualties occurred in one passenger coach of the train, which was coming from the eastern city of Lahore, he said.

Pakistan suffered its worst train disaster in more than a decade in 2005 when three trains ploughed into each other in southern Sindh province, killing around 150 people. More than 350 people were killed in a 1990 train smash.