Two passenger trains derailed over a bridge in central India while crossing a track that was flooded by heavy monsoon rains, killing at least 24 people.

More than 300 people have been rescued, and there are fears some passengers may still be trapped.

The Kamayani Express was on its way to Mumbai when it derailed night near the town of Harda in Madhya Pradesh state, while the Janata Express was travelling in the opposite direction when it derailed soon after.

The trains were crossing a small bridge near the rain-swollen Machak River, about 590 miles south of New Delhi.

Another train had passed the same culvert 10 minutes before the first derailment without any problem, but then a flash flood caused part of the track to sink into the rain-soaked ground, said AK Mittal, a senior railway officer.

Six coaches from the Kamayani Express and the engine and four coaches from the Janata Express derailed. The accident occurred just before midnight local time, and although rescue workers soon reached the site, their efforts were hampered by the darkness, officials said.

At least two carriages had been partially submerged in the mud, said railway official Anil Saksena. While most people had been pulled to safety, rescue workers were still searching for passengers feared to be trapped.

"We are getting reports that there were flash floods and the tracks caved in. Most of the coaches had passed but the last few carriages were derailed," Mr Saksena said.

At least 24 bodies have been recovered so far and one person was seriously injured, said Bijendra Kumar, a railway official in Bhopal, the main city in Madhya Pradesh state.

Junior home minister Kiren Rijiju said more than 300 people have been rescued.

The unaffected carriages have now been moved from the tracks and rescue operations are nearing a close. Railway workers will soon start repairing the tracks so traffic can resume.

Dozens of trains have been blocked from moving due to the accident, while others have been diverted to other routes.

The rain eased today following two days of heavy downpour.

India has one of the world's largest railway networks and carries more than 23 million passengers each day. However, many parts of the vast network are poorly maintained and accidents are common.

While many trains are called express, they rarely travel faster than 30mph.