QUETTA, Pakistan (Reuters) - Pakistani police on Wednesday found 15 bullet-ridden bodies of kidnap victims near the border with Iran, a favored route for human traffickers taking workers illegally to Europe.

The bodies were found abandoned in a mountainous region of Buleda, in Baluchistan province, 600 km (370 miles) south of the provincial capital of Quetta, district commissioner Bashir Ahmad Bangalzai told Reuters.

He said documents and other belongings found on the bodies suggested that they were en route to Iran illegally.

Human smuggling is big business in Pakistan and other poor South Asian countries. There have been instances of workers being killed in border areas, or sometimes dying during road or sea travel.

It was not clear what prompted the killings, said Bangalzai. He said all 15 came from Pakistan’s eastern province of Punjab.

“We’re getting in contact with their families,” he said.

A police official said all 15 were reported to have been kidnapped on Tuesday.

No one has claimed responsibility.

Violence-plagued Baluchistan, which also borders Afghanistan, has long been home to separatist groups seeking a greater share of regional resources and Islamist militants linked to al Qaeda, the Taliban and Islamic State.

The violence has raised concerns about security for projects in the $57 billion China Pakistan Economic Corridor, a planned transport and energy link from western China to Pakistan’s southern deep-water port of Gwadar.