Suspected tribal militants, fighting for greater political and economic autonomy, blew up a railway line linking southwestern Pakistan to Iran early on Saturday, a railway official said.Four bombs exploded at the railway track near the town of Noshki in southern Baluchistan province several hours before the train bound for the Iranian border town of Zahedan was due to pass. Noshki is 60 miles southwest of Quetta, capital of Baluchistan.
"The train was stopped shortly after it left Quetta. No one was hurt in the blast," Mohmmad Mushtaq, a senior railway official in Quetta, told Reuters.
He said a fifth bomb remained unexploded and efforts were being made to defuse it.
No one claimed responsibility for the blasts but the government has previously blamed Baluch militants for such attacks.
Meanwhile, security forces have detained 13 suspected militants in a crackdown, backed by helicopter gunships, in the town of Dera Bugti, a stronghold of a rebel tribal leader.
There were no immediate reports of any casualties in the operation that was carried out late Friday night, a local official said on condition of anonymity.
Baluchistan, bordering Iran and Afghanistan, is the largest but the poorest of Pakistan's four provinces and has the country's largest gas and oil reserves.
Baluch militants regularly blow up railway links, gas pipelines and power pylons, and launch attacks on government buildings and army bases to press for their demands for more benefits from oil and gas exploration. The simmering revolt escalated in December when rebels fired rockets during a visit by President Pervez Musharraf to the town of Kohlu.
Musharraf has announced plans for major infrastructure projects in Baluchistan but has vowed to deal firmly with the rebel leaders.