SRINAGAR -  Several unidentified gunmen attacked a camp housing road construction workers in the Indian-occupied Jammu and Kashmir on Monday, killing three labourers before fleeing, said police in the restive region near the border with Pakistan.

Two or three gunmen launched the raid on the General Reserve Engineer Force camp in Jourian, close to India's disputed border with Pakistan, after midnight, a police official from Jourian told a news agency.

The army had since cordoned off the camp and launched a search for the gunmen, said the official, who asked not to be identified because he was not authorised to speak to the media.

The area has been relatively calm in recent weeks following an upsurge in cross-border firing after a deadly attack on an Indian army base in September that New Delhi blamed on militants from Pakistan.

"Terrorists fired at the camp at 1:30am and killed three casual labourers. A search operation is launched to nab the attackers," army spokesman Manish Mehta told a news agency.

Rebel groups have for decades fought 500,000 troops deployed in the Indian-occupied part of Kashmir, demanding independence or a merger with Pakistan. Tens of thousands have died in the fighting, most of them civilians.

India has been fighting a revolt against its rule there since the late 1980s, and accuses Pakistan of supporting militants.

Pakistan denies this and says it only provides moral support to a Muslim-majority Kashmiri population angry with Indian rule.

Violence has risen since an attack on an Indian army base in September killed 19 soldiers.

According to the South Asia Terrorism Portal, which tracks violence, 267 people were killed in Jammu and Kashmir state last year, the highest death toll since 2010.