The Indian Army is investigating the possibility that militants who attacked its base in Uri, Kashmir, on Sunday could have had help from inside the camp, The Indian Express reported. Sources told the English daily that the militants were aware of key areas inside the camp, including the brigade commander’s residence and office, and also knew about troop movements. The attack on Sunday killed 18 Indian soldiers. Ten militants were also killed in a separate infiltration bid at Uri on Tuesday.

The report added that the militants who attacked the Army camp on Sunday avoided several security check-posts. Investigators are also looking into how the militants entered the base, including a way from nearby village Sukhdar.

The National Investigation Agency’s inquiry into the attack has also revealed that the militants possessed information about various locations at the camp. A number of casualties occurred at a cook-house and store room, which the four militants had locked and set fire to, according to The Indian Express.

Security along the Line of Control has reportedly been increased after the attack, while parts of Srinagar remain under curfew. Kashmir has seen more than two months of unrest and violence after Indian forces killed Hizbul Mujahideen commander Burhan Wani on July 8. The unrest and attack at Uri have both contributed to worsening ties between India and Pakistan.