Nearly 200 devotees attending a religious congregation at 'Nirankari Bhavan' in Amritsar rushed for safety after unexpectedly being pushed into chaos on Sunday, when two men on a motorcycle hurled a hand grenade in an apparent terror attack at the premises, from where messages of peace and spirituality are sent out, eyewitnesses said.

Recalling the scenes that followed the attack on "Nirankaris", the eyewitnesses said they were panicked, shocked and scrambled through a thick blanket of smoke.

They said it was a usual Sunday congregation at the Bhavan on the outskirts of Amritsar city, until the bombers struck.

"Each Sunday, I do 'sewa' at the Bhavan. I was on duty near the stage when I saw a person, who appeared young, with his face covered, throw something and run. The next thing I remember is that there was a blast, smoke all over and everyone ran around for their lives, Simranjeet Kaur told reporters outside the premises.

A man said his daughter was deputed at one of the entry gates to frisk women devotees visiting the place.

"She told me that two people came there and pointed a pistol at her after which she panicked. The next thing she knows that people were rushing out in fear after a grenade was hurled inside," he said.

A devotee who was inside the Bhavan said, "I saw blood at the spot after the blast. Although I did not see the attackers, I was told by other devotees that two youth had come on a motorcycle. They gained entry inside and hurled explosive and escaped. Both appeared to be youth with faces covered".

Another man, who identified himself as Gurpreet Singh, said he lives near the Bhavan, which is also close to the Amritsar international airport.

"I was in my home when someone said a cylinder had burst at Nirankari Bhavan. When I reached there, I saw injured people being taken to hospital in ambulances," he said.

Pawandeep Singh, an ambulance driver, said he took many seriously injured to Guru Nanak hospital in Amritsar. Injured people were also rushed to a private hospital.

The grenade attack has left three people dead and at least 10 injured, police said. The Punjab police chief said they were treating it as a terrorist attack. DGP Suresh Arora told PTI that the attack "appears to have a terror angle... we will take it as a terrorist act."

Punjab was put on alert following an input claiming that a group of six to seven JeM terrorists were reportedly in the state, possibly in Ferozepur area.

Four people had carjacked an SUV at gunpoint last week near Madhopur in Pathankot district.

(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)