The Pathankot attackers were in regular touch with their handlers in Pakistan, who even hailed a taxi for them using a mobile number registered in that country, security agency sources have claimed.

The family of the driver of the Toyota Innova, who was called from the Pakistan number, is being questioned. The investigators want to know if he had been regularly ferrying smugglers from that country who had links with the militants or did not realise that he had been dialled from across the border, the sources said.

The militants had boarded the Innova on Thursday from a place near Pathankot from where they took an unmetalled road. The vehicle was dumped after a while as its rim got damaged, the sources said.

The attackers, who were in army uniform, then hijacked a Mahindra XUV 500 in which a superintendent of Punjab police was travelling with a friend and a cook. The terrorists snatched a mobile phone from them and used it to dial the same number in Pakistan that had been used to hail the Innova. The SP and the cook were pushed out of the vehicle while the friend, a jeweller, was taken hostage, the sources said.

Three calls were made to the handlers from the snatched phone and one was made to a family member who was told they were on a suicide mission, the security agency sources said. The handlers were actively giving them directions.

Since the Pakistan number was under surveillance, security agencies were able to find out the possible target of the attack, leading to dispatch of 160 NSG commandos and army special forces, the sources claimed.

Residents of Dhaki Chowk in Pathankot woke up to the sound of gunfire and blasts at 3.30am, but they had been warned of an imminent attack last evening.

"We were asked by the police to close down our establishments after the abduction of an SP (on Thursday night) and recovery of his vehicle from near Palta Sahib Gurdwara (yesterday). It triggered fear among us of a possible terror attack," said Rahul, who runs an inverter shop and whose house is close to the boundary wall of the Indian Air Force station that came under fire.

The shopkeepers and the handcart pullers closed their businesses and rushed home and security personnel were deployed in the area around 6pm.

"Intelligence inputs had been available of a likely attempt by terrorists to infiltrate into the military installation in Pathankot area. In response, preparatory actions had been taken by the Indian Air Force to thwart any such attempt," said an IAF statement issued in Delhi today.

A team of NSG commandos arrived in Pathankot from Delhi last night. Two army columns were also positioned here.

"We run a tea stall which remains open till late in the night because travellers on the highway stop here for tea. I was asked by security authorities to close the shop and go home. We are thankful to the security alert," said Swatanter Singh, who runs a tea stall close to the air force station.

Security personnel had set up checkpoints and started patrolling the area since last night.

"We woke up in the middle of the night to a sudden barrage of fire and sounds of blasts. Our family huddled in a room," Rahul said.

People came out in Dhaki Chowk in large numbers during the day to shout slogans against Pakistan even as the operation was on inside the air force station.