July 27: Heavily armed, unidentified terrorists attacked a police station in Punjab today, fought security forces from dawn to dusk and killed a senior police officer and six others before three attackers were shot dead.

Three civilians and two home guards were killed by the militants in army fatigues in their deadly run to take over Dinanagar police station, northeast of Gurdaspur and less than 15km from the international border with Pakistan as the crow flies.

The militants were gunned down by Punjab police's "Special Weapons and Tactics" (SWAT) team, which was set up four years ago to tackle 26/11 Mumbai-style attacks and deployed today for the first time in a real-time operation.

Officials hailed the fledgling force for averting what could have been a greater tragedy and a long-drawn stand-off. But, from the operational point of view, questions have been raised whether at least one of the terrorists could have been captured alive just as Ajmal Kasab was caught during the 26/11 attacks.

Sources in the Punjab police claimed that the operation lasted nearly 12 hours because they wanted to catch at least one attacker alive. The Punjab police also asked the army and the National Security Guard, detachments of which were sent to Dinanagar, to stay away from the zone of fire.

This was as much because the Punjab police wanted to avenge the killing of their SP, Baljit Singh, as because, they claimed, they knew the terrain best since it was their police station. The decision to keep specialist troops who were available out of the action may be debatable.

Some sources said the absence of bullet-proof vehicles in Gurdaspur delayed the final onslaught. The vehicles were eventually sent from Jammu and Kashmir.

Shoe shop owner Amit Sharma said he was woken by the sound of gunfire at dawn. "I thought someone was setting off firecrackers," Sharma said. Instead, he saw three men with assault rifles "spraying bullets everywhere".

Throughout the day, regular bouts of small-arms fire echoed across the town and the surrounding paddy fields.

The police station was located among a cluster of buildings, some of which were abandoned police quarters while one was a hospital.

"It is a very serious terror attack," national security adviser Ajit Doval said after a review with the home minister and the defence minister in Delhi.

"The terrorists were heavily armed. Their grenades were marked 'Made in China'. They carried GPS," said Punjab director-general of police Sumedh Singh Saini, who supervised the operations in Gurdaspur. Reuters quoted Saini as saying in the evening it was "too early to say" where the gunmen had come from.

The militants are as yet unidentified. Sources in the home ministry said this morning's attack mirrored a pattern seen in the recent past and bore the hallmark of the fidayeen of the Lashkar-e-Toiba, who had attacked a police station and an army camp at Hiranagar and Samba in neighbouring Jammu in September 2013.

Intelligence and security agencies in the home ministry have concluded that the early morning attack in Gurdaspur - the first ever in Punjab, apparently, by a Kashmir-centric group - was by a three-man fidayeen or suicide squad of the Lashkar-e-Toiba or the Jaish-e-Mohammed.

But R.K. Singh, a BJP MP and a former Union home secretary, told a television news agency that the Centre must reckon with Sikh militants who were being controlled by Pakistan's Inter Services Intelligence. The news channel NDTV quoted a homeguard at the spot saying that he saw one of the attackers "wearing a turban". Government sources said there was no Sikh among the attackers.

Security forces did report a ceasefire violation in Hiranagar in Jammu last evening that may have given infiltrators from Pakistan covering fire. Five bombs were found on the railway tracks between Gurdaspur and Pathankot.

Dinanagar is inside Punjab and close to the inter-state border with Jammu. National Highway 15, which connects with National Highway 1A leading to Jammu and Kashmir, runs by it. To its west is the international border, which runs on flatland marked by marshes and the tall sarkanda grass. It is on a "chicken's neck" between the border and the hills.

Pakistan was quick to condemn the terror attack.

"We condemn in the strongest terms the terrorist incident in Gurdaspur, India, today, in which a number of precious lives have been lost," Qazi Khalilullah, Pakistan's foreign ministry spokesperson, said. "Our thoughts are with the bereaved families. Pakistan reiterates its condemnation of terrorism in all its forms and manifestations."

But Indian and Pakistani officials conceded that any cross-border link on the terrorists' part could make it politically harder for both sides to pursue talks.

Security forces in Jammu and Kashmir contested suggestions that the attackers had sneaked in from Pakistan-occupied Kashmir across the border in Jammu.

A BSF officer in Jammu said Dinanagar was at least 30km from the nearest point on Jammu's international border. "Kindly do not run stories in haste," the officer said.

The BSF is responsible for guarding the international border in Jammu. Militants have in recent years carried out similar attacks on security installations and civilians after crossing the border, which were a source of embarrassment for the security forces.

Other sources suggested the attackers entered the country through Bamiyal village in Pathankot, located in Punjab and close to the international border.

Ashkoor Wani, the deputy inspector-general of police in Jammu's Kathua range, said Punjab had requisitioned bullet-proof vehicles and jackets in the morning. "These things were soon dispatched. Our men, however, did not participate in the operation," Wani told The Telegraph .

An alert has been issued across the country in the run-up to Independence Day following the Dinanagar attack.