The Centre today issued a country- wide alert asking states to step up vigil to foil any attempt by Pakistan-based terror groups to avenge the surgical strike on their launch pads in PoK even as Home Minister Rajnath Singh reviewed security situation along the Indo-Pak border.

Security agencies were also apprehending stepped up action by militants currently operating in Jammu and Kashmir targeting security forces and civilians following yesterday's surgical strike by special forces of the Army on seven terror launch pads in Pakistan-occupied Kashmir(PoK).

Security was strengthened at vital installations across Punjab and a high alert has been sounded at all airbases across the state while evacuation of people residing in villages along the International Border continued.

During the hour-long meeting with the country's top security brass, Singh instructed the officials to ensure that the forces posted along the border remain on alert as the situation along the Indo-Pak border continues to be volatile, official sources said.

The Army, meanwhile, trashed reports in Pakistan about Indian casualties during the operation, saying one member of the special forces received minor injury during exfiltration but it was not due to any enemy or terrorist action.

The operation was a clinically planned one and the attack on the seven launch pads were carried out simultaneously, sources said.

The sources said it was a moonless night and total darkness helped the special forces bring in the element of surprise with total effectiveness.

It has been estimated that casualties was at least 40 on Pakistani side but there was no official confirmation.

Choppers also hovered over several sectors on the Indian side of the LoC to divert attention of the Pakistani security forces guarding various posts.

There were unconfirmed reports that the operation has been videographed using drones. There have been satellite images of the operation as well, the sources said.

In an advisory, the Home Ministry conveyed to the states that additional forces should be deployed in all sensitive places, strategic installations, markets, religious places and other key places to ensure security, the sources said keeping in mind the upcoming festive season.

Metro cities were particularly asked to be extra vigilant.

States touching the border with Pakistan -- Jammu and Kashmir, Punjab, Rajasthan and Gujarat -- were also directed to remain vigilant.

Sources said there is high probability that Pakistani agencies may try to use the terror groups to carry out strike in Indian soil to avenge the attack.

The country's top security brass briefed the Home Minister about the situation along the border and steps being taken to foil any Pakistani design to attack BSF posts besides safety of civilian population living in forward areas.

Those who attended the meeting include National Security Advisor Ajit Doval, Union Home Secretary Rajiv Mehrishi and top officials of security and intelligence agencies.

BSF, which comes under the Home Ministry, has already put all its units along the Indo-Pak border on "high alert".

Orders have been issued to all its units along IB in Jammu, Punjab, Rajasthan and Gujarat to step up vigil and bolster their numbers at the posts by bringing in all personnel who are in the reserve.

BSF has also restricted all civilian movement along borders with Pakistan. The border guarding force has also been asked by the Home Ministry to provide manpower to local administration for helping in evacuating people from border villages to safer locations.