ISLAMABAD, Pakistan — At least four people were killed and nearly 90 injured on Thursday when a commuter train carrying Pakistanis returning to work after a three-day holiday rammed into a freight train in central Pakistan, officials said.

The early morning accident occurred about 15 miles from Multan, a city in Punjab Province. The freight train was sitting idle after it had struck a man on the tracks when an Awam Express train bound for Karachi smashed into its rear, Nadir Chattha, a local official, was quoted as saying by the news media.

It was not immediately clear whether the man had committed suicide or had been struck while trying to cross the tracks.

Human error appeared to have caused the accident, officials said.

“The driver of the passenger train did not see the red signal, which went up after the man was crushed to death by the freight train,” Saima Bashir, a railroad official, told The Associated Press.