Three persons were killed and at least 10 injured in a grenade attack on a prayer hall brimming with around 200 devotees on the outskirts of the city on Sunday.

The blast occurred during a religious gathering of the Nirankari sect at Nirankari Bhavan in Adliwal village near Amritsar's Rajasansi, which is close to the international airport.

According to eyewitness accounts, the grenade was lobbed by bike-borne persons.

Meanwhile, Punjab police said that the grenade attack on a religious congregation 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.

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.

Union Home Minister Rajnath Singh spoke to Chief Captain Amarinder Singh and promises strongest possible action against the culprit.

"Spoke to the Punjab CM Captain Amarinder Singh ji who has apprised me of the situation in the wake of grenade attack in Amritsar. Strongest possible action will be taken against the perpetrators of this crime," Singh said.

Singh also expressed his condolences to the families who have lost their loved ones in this attack & prayed for speedy recovery of the injured.