However, the police denied any blast in the police station.

According to locals, an explosion was heard at around 3 a.m. Senior police officials reached the spot and were investigating the matter.

Amritsar Police Commissioner Gurpreet Singh Bhullar denied claims of a blast. He said locals heard the sound of the explosion, but there was no damage there.

It's learnt that a Germany-based gangster Jeevan Fauji claimed responsibility for the blast.

Three days ago, three members of the Khalistan Zindabad Force (KZF) module were arrested in connection with a hand grenade attack at a police post in Nawanshahr in Punjab, Director General of Police (DGP) Gaurav Yadav said.

The accused were identified as Yugpreet Singh, Jaskaran Singh and Harjot Singh. Police teams also recovered two weapons -- one country-made pistol and one revolver -- along with six cartridges from their possession.

That development comes less than two weeks after some miscreants targetted the police post at Asron by hurling a hand grenade on its premises on December 2.

DGP Yadav has said the accused are the members of the KZF module controlled by handlers based in Germany, Britain and other countries and were tasked to target police establishments and minority leaders in Punjab and Haryana. The module has received funding of Rs 4.5 lakh in six months.

He had said preliminary investigation revealed that the arrested people had retrieved a hand grenade from a dead letter box (DLB) located in Jalandhar on November 28 and hurled it at the police post on December 2. A DLB is a secret location used to exchange information or items between two people without meeting in person.

Sharing operation details, Assistant Inspector General (Jalandhar) Navjot Singh Mahal said that a team of CI Jalandhar along with SBS Nagar Police laid a checkpoint near the railway crossing in SBS Nagar city and arrested the accused when they were coming on a motorcycle. Police teams have also impounded their motorcycle, he added.

He said further investigations are underway to identify and arrest other members of this terror module.