Updated

Suspected Islamic militants set off a bomb along the main highway in India's troubled Kashmir state Monday, killing 13 paramilitary police and leaving at least five injured, officials said.

The men were traveling in a truck near the town of Ramsoo, about 100 miles south of Srinagar, when the bomb threw the truck into a deep ditch, said Neeraj Kumar, spokesman for India's Border Security Force.

The Pakistan-based Hezb-ul Mujahedeen, the largest guerrilla group in Kashmir, claimed responsibility for the attack, Press Trust of India news agency reported.

Traffic was stopped along the highway after the afternoon blast as security forces looked for more explosives, he said.

In a separate incident, Ghulam Nabi Chuntsaz, an activist with the pro-India National Conference party, was shot dead Monday by unidentified gunmen outside the party's former office in downtown Srinagar, a police official there said on condition of anonymity.

Militants have waged a 12-year insurgency for the independence of Indian-controlled Kashmir or its merger with Muslim Pakistan. More than 60,000 people have been killed and thousands are missing.