The service, launched April 7 after a gap of almost 60 years, is bitterly opposed by some hardline rebel groups who have threatened to turn the vehicles into "coffins".

Two buses carrying 42 passengers left the Indian Kashmir summer capital Srinagar for the Line of Control, the de facto border dividing arch-rivals India and Pakistan in the disputed region, at around 8.00 am, a police spokesman said.

On board were 18 Indian Kashmiris visiting the Pakistani zone of the Himalayan region and 24 who were returning home after travelling two weeks ago to the Indian side on the fortnightly bus.

The two buses take the passengers only up to the Kaman Post on the LoC, where passengers from both sides cross a bridge by foot and board buses from the other side.

"We have sanitised the entire strip of road between Srinagar and Kaman Post," the police spokesman said.

Security convoys have been attacked along the 118-kilometer road in the past.

"We have taken the threat very seriously and before allowing the buses to ply on the road we check for boobytraps and landmines," the spokesman said, adding that sniffer dogs had also been pressed into service.

The reinstatement of the bus service is the most visible sign of progress in the slow-moving 18-month-old peace process between India and Pakistan aimed at ending their bitter dispute over Muslim-majority Kashmir, spark of two of their three wars since independence from Britain in 1947.

Moderate separatists used the service on June 2 to cross into the Pakistani portion of Kashmir and later to Pakistan. They returned June 16 after holding talks with politicians and officials on the other side.