At least 35 illegal migrants died of suffocation inside a shipping container found Saturday in southwest Pakistan near the border with Afghanistan, police said.

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

More than 100 people were inside the metal container when police opened it on a tip-off, Bakhsh said. Some were taken to the hospital unconscious and the death toll could rise, he said.

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

Officials ordered an 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.