Pathankot: Defence Minister Manohar Parrikar admitted on Tuesday that "security lapses" led to the terrorist attack on the IAF base here that left seven security personnel and six terrorists dead. Parrikar also told the media after visiting the base that combing operations were still going on but "this is only for safety purposes" and that no more terrorists were believed hidden in the huge complex. Some gaps led to security lapses, leading to the pre-dawn terror attack on Saturday, the minister said. He did not elaborate. "What is worrying is how they (terrorists) entered the base," he added. Parrikar visited the Pathankot Indian Air Force base in Punjab on Tuesday along with the chiefs of the army and air force. The head of the National Investigation Agency (NIA), which is probing the audacious terrorist strike, also visited the base separately. "Combing operations are (still) going on," Parrikar said. "This is only for safety purposes." He said the body of one of the terrorists still had a suicide vest, with a grenade sticking out. "I am very, very clear that they (our officers) should not take any risk," he said, recalling how a National Security Guard (NSG) officer lost his life earlier while trying to reportedly shift a similar body. Parrikar admitted that the entire operation "is a very difficult" one. "It is tedious. This has been done without compromising any assets... Not just the strategic assets but even a building." He said barring one building where the terrorists took shelter, no other building was even damaged because the security personnel managed to corner the raiders in a corner of the sprawling base. He said the terrorists had AK-47 rifles, pistols, Swiss knives, commando knives besides 40-50 kg of bullets. They also had improvised mortars. "They had high quality explosives." The minister said the NIA had started investigation into the attack. He said it would find out "who sent them". "They have got initial leads, where they have come from, how they have come."