At least 62 people suffocated to death in a truck container packed with illegal migrants from Afghanistan, and dozens were rescued unconscious Saturday after Pakistani police acting on a tip opened the container near the border.

Rasool Bakhsh, a senior police official in the city of Quetta, said the shipping container the truck entered Pakistan from Afghanistan and was headed for Iran. He said most of the victims were Afghans.

More than 100 people were packed inside the 12-metre-long metal container, Bakhsh said. Survivors were taken to hospital, many of them unconscious.

Khalid Masood, another senior officer, said 62 migrants were pronounced dead.

Television footage shot shortly after the white container was opened showed dozens of bodies, many of them stripped to the waist, lined up on the road next to the truck.

The stench from the container suggested some might have been dead for days, Bakhsh said.

Officials said they were holding the truck's driver as part of their investigation.

Southwestern Pakistan lies on a well-trodden route for traffickers smuggling young men from poverty-afflicted countries, including Afghanistan and Pakistan, hoping to find work and prosperity in Europe and elsewhere.