SRINAGAR: Sniper attack by Jaish-e-Mohammed terrorists has emerged as a new source of worry for security agencies in Kashmir Valley with three personnel having been killed since mid-September, prompting the law enforcement agencies to re-calibrate their strategy to thwart such strikes by the Pakistan-based group, officials said.The first such attack took place at Newa in Pulwama on September 18 when a CRPF personnel was injured. Security officials thought it to be a one-off strike till the recent spate of sniper attacks that claimed the lives of a Sashastra Seema Bal jawan and an Army personnel in Tral, and a CISF jawan in Nowgam.Based on intelligence inputs, security agencies believe that at least two separate 'buddy' groups of the proscribed Jaish-e-Mohammed (JeM) comprising two terrorists each have entered Kashmir Valley in early September and have entrenched themselves in South Kashmir's Pulwama district with the help of some overground supporters of the outfit.These terrorists, according to the officials, have been thoroughly trained by Pakistan 's external snooping agency ISI for carrying out sniper attacks in Kashmir Valley and have been armed with M-4 carbines, used by the US-led allied forces in Afghanistan.There is a possibility that these weapons may be part of the arms and ammunition captured by the Talibans, with whom the JeM cadre were fighting the allied forces in Afghanistan, security officials in the state said. However, they said that the weapon was also being used by the special forces of Pakistan Army In all the instances of sniper attacks, the terrorists used a nearby hillock to carry out strikes on a security force campus when unsuspecting jawans were using their mobile phones to talk to their family or friends."These attacks have been precise, even while targeting a personnel inside a sentry post as he uses his mobile phone. They pick up the light of the mobile phone to carry out the attack on jawans," said one of the officials.Former Jammu and Kashmir Chief Minister Omar Abdullah has reacted to the rising cases of sniper attacks. "We've dealt with snipers on the border/LoC regularly and have SOPs to deal with those but never in the hinterland. This will force a rethink of all manner of security and protection procedures."The M-4 carbine is mounted with a telescope and the terrorists are using night vision devices to locate their potential targets, the officials said. The weapon can fire at its target up to 500-600 metres with precision.The security agencies, including army, CRPF and Jammu and Kashmir police, have already issued fresh guidelines to their jawans and officers located in camps in the militancy-hit areas.Maintaining a silence over the change in tactics, the officials said that more combing operations would be carried out around the security camps.They said that Jaish cadres were likely to carry out more such attacks in the future, but added that some modules had been identified and these cases were likely to be cracked soon.The security agencies had been observing that while pushing the terrorists into Kashmir Valley from the Line of Control (LoC), ISI meticulously planned to send in Jaish-e-Mohammed cadre along.Those terrorists were armed with the best possible arsenal including bullets with steel core – with the capability to pierce a static bullet proof bunker used during counter-terrorism operations, the officials said.The first such incident was noticed on the New Year eve when JeM terrorists had carried out a suicide attack on a CRPF camp in Lethpora in South Kashmir. Five personnel of the para-military force were killed in the attack and one of them was hit by a bullet fatally despite using a static bullet-proof shield provided by the Army, officials said.A thorough inquiry into the attack showed that the bullet fired by the terrorist from the assault AK rifle was of steel core with the capability of piercing through the static bunkers used by security personnel during encounters with terrorists.Generally, the AK bullets used in the armoury have a lead core covered with mild steel which cannot penetrate a bullet proof shield but after the December 31, 2017 encounter and subsequent findings, the rules of the proxy-war changed, the officials said.A detailed analysis of the previous suicide attacks was carried out during which ballistic analysis of the terror attack on district police lines of Pulwama in South Kashmir in last August showed that 'steel core' bullets had been used by the terrorists in that encounter with security personnel. Eight security personnel had lost their lives in the terror strike.The ammunition, according to the officials, is being modified from across the border with the help of Chinese technology of encasing the bullet with hard steel core.At the United Nations, India has been seeking a ban the Jaish-e-Mohammed terror group and designation of its chief Maulana Masood Azhar as global terrorist, but its efforts have been blocked by China four times so far.