Of the four calls made, three were to handlers in Pakistan, in which the terrorists reported the assault made on a senior police officer in Punjab. In the fourth, an attacker was heard calling his mother, sources said.
On Thursday, the men, dressed in army fatigues, had hijacked the official vehicle of the police officer in Pathankot.
They had assaulted the officer, pushed him off the car and took away his cellphone. Later, they used his cellphone to contact their handlers in Punjab, sources said.
The handlers were heard asking the men why they "let off" the Superintendent of Police.
The intercepts triggered a whirlwind of activity - a warning was issued and National Security Adviser Ajit Doval held a meeting with security officials.
Following orders from the Prime Minister's Office, teams from the National Security Guard, Special Forces of the Indian Army and additional soldiers were moved to various installations at Pathankot.
But notwithstanding the protective measures, the terrorists struck at 3.30 am. The gunbattle, which carried on well-past mid-day claimed the lives of two Air Force personal and one Garuda commando.
Given the advanced information, the terrorists were contained within the periphery of the air base. The army's Casspir armoured personnel carriers were used to close in on the administrative block of the air base, where the terrorists were holed up.
Four terrorists have been killed in the operation.
The men, sources said, had infiltrated just hours before, sources have told NDTV. They had, in all likelihood, crossed into India from the unfenced section of the international border and proceeded towards Punjab, the sources said.