Abu Huzaifa, the spokesman for the Lashkar-e-Taiba group, told the Greater Kashmir newspaper on Tuesday that civilians should stay away from potential targets.
The newspaper said: "People should keep themselves away from the security installations as according to him (Huzaifa) they could become the unintended targets of such attacks."
Huzaifa urged Kashmiri Muslims to pray for the victory of all Islamic groups fighting in Kashmir and elsewhere in the world.
"Mujahidiin are fighting occupational forces not only in Kashmir but also in Palestine, Iraq, Chechnya and the Philippines. In this holy month we appeal to people to pray for the success of our mission," he said.
And he rejected a recent offer from New Delhi to open a dialogue with the separatists.
"People should not take these peace offers seriously as eventually these are destined to come to nought," he said, adding Islamic groups were the true representatives of Kashmiris and not politicians.
"The mission of mujahidiin is to liberate Kashmir from India," Huzaifa said.
"Mujahidiin are fighting occupational forces not only in Kashmir but also in Palestine, Iraq, Chechnya and the Philippines. In this holy month we appeal to people to pray for the success of our mission"
Ramadan began in Kashmir on Tuesday, with Muslims filling mosques for dawn prayers across the restive Himalayan state.
The region, divided between nuclear-rivals India and Pakistan and claimed in full by both, usually sees a rise in violence during the sacred month.
Lashkar is one of a dozen groups fighting Indian troops in Kashmir. Rebels want to separate Kashmir from India and join it with neighbouring Pakistan or remain independent.
Lashkar and another group Jaish-e-Muhammad, both formed in Pakistan, were blamed by India for an attack on its parliament in December 2001 that killed 15 people.
Pakistan and the United States have since banned both groups.
The 13-year insurgency in Kashmir has claimed more than 39,500 lives, according to Indian security forces. Separatists and Pakistan put the death toll between 80,000 and 100,000.