Punjab police said Sunday the grenade attack on a religious congregation on the outskirts of Amritsar city appears to be a "terrorist act".

"It (this incident) appears to have a terror angle. Because it is against a group (of people) and it is not against any individual. There is no reason to throw a hand grenade on a group of people, so we will take it as a terrorist act. Till proven otherwise, prima facie we will take it as that," Punjab Director General of Police Suresh Arora told PTI.

To a question, the DGP said there was no specific input about any possible attack on Nirankari Bhavan.

"There was no issue with this group as such… There was no specific input on (Nirankari Bhavan)," he said.

Three persons were killed and at least 10 injured in a grenade attack on a religious congregation on the city outskirts on Sunday, police said.

The attack took place inside the Nirankari Bhavan at Adliwal village near Amritsar's Rajasansi, close to the international airport, police said.

A religious congregation of the Nirankari sect was being conducted inside the Bhavan at the time of the incident.

"A grenade was lobbed and three people have died in the incident while 10 have been injured in the incident, two of them critically," Inspector General of Police S S Parmar, who visited the incident spot, told reporters.

He said about 200 devotees were inside at the time of the attack. No CCTV camera was installed at the premises, preliminary investigations found, he said.

"We have launched relief and rescue operations," he said.

After the attack, Punjab Chief Minister Amarinder Singh reviewed the law and order situation and directed the Home Secretary, DGP (Law and Order) and DG Intelligence to rush to Rajasansi to supervise investigations.