NEW DELHI: Another Indian Army jawan succumbed to his injuries sustained during a terrorist attack on an army unit’s administrative base in Uri on Sunday, raising the death toll to 18.Earlier in the day three army personnel, who were critically injured in the attack, were referred to the force’s Research and Referral Hospital in Delhi.The army believes that the four terrorists had possibly infiltrated through two locations at the Line of Control (LoC). The locations are only six to seven kilometres away from the base. The terrorists had possibly infiltrated through either Churunda, located at a height, or Islamabad Nallah, which flows in and out of India.The terrorists who were in army fatigues had possibly arrived near the base either on Saturday night or during the early hours of Sunday. "It was not like the Pathankot attack, wherein the terrorists had spent the night in the base,” said an official, adding the attack took place at a time during the handing and taking over of two units.The terrorists had arrived near the base through a nallah near it. They entered the base after cutting through the fence around it. The terrorists opened fire at the toilet area at about 5.15 am on Sunday. They then opened fire at the tents, located about 150 metres away from the toilets. “The men were sleeping in the tents,” said another official.The kote (the storage facility for the arms) also caught fire. An assessment of the losses is being made. Barrels of diesel and kerosene located near the MT (Mechanical Transport area, where vehicles are parked) and the cook house also caught fire."The terrorists lobbed 17 grenades in three minutes, igniting the diesel dump and creating a massive fire, which burnt the barracks and tents in an area of 150 metres. Thirteen soldiers were burnt alive and 32 others were injured with severe burns," said the official.When the diesel dump exploded, the smog and the subsequent explosion disoriented the terrorists and they headed towards the soldiers barracks. A terrorist was gunned down by a 19 year old soldier. "He challenged the remaining three terrorists and sustained a severe head injury when a bullet hit his helmet. He was evacuated by his colleagues," said the official.Since the barracks was empty the terrorists took defensive position inside the barracks at the second floor. The army’s Special Forces stormed the building and eliminated them.