Amritsar, Nov 18 (IANS): Three people were killed and at least 15 others injured when two motorcycle-borne masked youths threw a grenade at a religious congregation in Rajasansi area in Punjab's Amritsar district on Sunday, police said.

The grenade attack took place on the Nirankari Satsang Bhawan of the Nirankari sect in Adliwala village, about 15 km from Amritsar. The sect campus is located in Amritsar's rural belt.

The injured were rushed to hospitals in Amritsar. A few of them were in serious condition, police said. All victims were sect followers from nearby villages who had gathered for the Sunday weekly religious meeting.

Witnesses told the police that two youths on a motorcycle, their faces covered, forced entry to the sect campus by pointing a pistol at a woman volunteer at the gate.

"Everything happened within a couple of minutes. They got in, threw the grenade and fled," one man told the police.

The attack came amid a high alert issued on November 14 by the Punjab Police regarding the movement of 6-7 terrorists in the state.

Punjab Police Inspector General (Border Range) S.P.S. Parmar confirmed to the media that three people were killed in the grenade attack.

Asked if it was a terror attack, Parmar said that all angles were being investigated.

"The people had gathered for prayers. There were around 200 people. Preliminary reports suggest that the two persons threw one grenade. Three people have been killed and 15 to 20 are injured. No firing took place," Parmar said.

"We are investigating the incident from all angles," Parmar said.

Senior police officers rushed to the village following the grenade attack.

Congress legislator Raj Kumar Verka told the media that no compromise would be made by the Congress government in Punjab on terrorism.

"We will deal with it strictly," Verka said, admitting that the incident showed intelligence failure on the part of the Punjab Police.

The Punjab Police, along with the Jammu and Kashmir Police, had recently busted two modules of Kashmiri students who were studying in institutions in Punjab and having links to terrorist outfits in troubled Kashmir.

Posters of Kashmiri terrorist Zakir Mussa had mysteriously appeared in Punjab's Gurdaspur district on Friday saying that he had been seen in Punjab.

The Nirankari sect has millions of followers across the country and abroad. The sect has its headquarters in Delhi.