People in Pakistan are desperately trying to locate their relatives and friends after a train crash killed at least 133 people and injured hundreds.
Many bodies have still not been claimed by relatives
Three packed passenger trains collided near the town of Ghotki in Sindh province on Wednesday. It was one of the country's worst rail accidents.
The names of the dead and injured have yet to be released.
But officials said 35 of the 127 bodies that been taken to the local hospital had been identified.
President Musharraf has said that anyone found negligent in relation to the crash would be prosecuted.
"We will immediately start an enquiry, and if there was any carelessness involved, it should be punished," he said.
Local officials say they have received hundreds of telephone calls from people trying to locate relatives and friends.
'In the dark'
Railway stations across Pakistan have been overrun by people wanting to read passenger lists for the affected trains.
"I am still waiting to find out the fate of my two brothers whom I saw off here on Tuesday on their way to Karachi but I haven't heard anything," Sohail told the AFP news agency outside Lahore station.
Mohammad Ilyas, who was searching for his sister along with her three children on one of the trains, said: "They [railway authorities] are not telling us anything at all."
Lutafullah Khan said he was "completely in the dark" about his two sons who were on a train.
"I will never smile again until I hear good news about my boys," he said.
The BBC's Aamer Ahmed Khan in Ghotki says that dozens of bodies - many of them beyond recognition - are still lying unclaimed at the local hospital.
Local ice factories have been supplying the hospital with huge blocks of ice to prevent the decomposition of the corpses.
More men and equipment are being sent to the crash site to speed up the work to clear the tracks.
Casualty figures are often high because of overcrowding
The accident happened at about 0400 (2300 GMT Tuesday) on the border between the provinces of Sindh and Punjab.
The express train heading from Lahore to Karachi slammed into the rear of broken down Quetta Express at a station near Ghotki, about 600km (370 miles) north-east of Karachi.
A third train travelling in the opposite direction, heading from Karachi to Rawalpindi - the Tezgam Express - then hit a number of derailed carriages, which were scattered over several tracks.
Abdul Wahab Awan, general manager of Pakistan Railways, said the conductor of the Karachi Express had failed to read a signal correctly.
Pakistani President Pervez Musharraf said he was "deeply saddened" at the crash and ordered an urgent investigation.
Pakistan is no stranger to train crashes involving multiple deaths. The BBC's Paul Anderson says casualty figures are often so high because trains are packed with far greater numbers than they were designed for.
More than 200 people were killed in a train crash in Sindh province in 1990. The following year more than 100 people were killed in another accident, also in Ghotki.
PAKISTAN TRAIN CRASH
1. Quetta Express, travelling from Lahore to Quetta, is stationary for maintenance work
2. Karachi Express, travelling from Lahore to Karachi, crashes into Quetta Express. Carriages derail across other tracks.
3. Tezgam Express, travelling from Karachi to Rawalpindi, crashes into derailed carriages