A rocket-propelled grenade hit the Punjab police's intelligence wing headquarters in Mohali near Chandigarh on Monday night, shattering windowpanes on one of the floors of the building, the police said.
No one was injured in the explosion, which political parties termed 'disturbing' and 'shocking'.
The explosion took place at around 7.45 pm at the office located in sector 77 in Mohali.
The windowpanes on one of the floors of the building were shattered because of the explosion.
'A minor explosion was reported at the Punjab police intelligence headquarters in sector 77, SAS Nagar at around 7.45 pm. No damage has been reported. Senior officers are on the spot and an investigation is being done. Forensic teams have been called,' the Mohali police said in a statement.
The police cordoned off the area and an alert has been sounded. A police official told reporters that there was no casualty in the incident.
"A minor blast took place at the intelligence building. The investigation is going on and our senior officials are on the spot," the police official said.
"The blast took place with a rocket-type fire. There is no casualty," the official stated.
Asked if it was a terror attack, the official said the investigation was going on.
The explosion came on the heels of the recovery of an explosive device near Burail jail in Chandigarh on April 24.
Former Punjab chief minister Captain Amarinder Singh (retd) urged Chief Minister Bhagwant Mann to take strict action against those who were behind this incident.
'Shocked to hear about the blast at the @PunjabPoliceInd Intelligence headquarter in Mohali. Thankfully nobody was hurt. This brazen attack on our police force is deeply concerning and I urge CM @BhagwantMann to ensure perpetrators are brought to justice at the earliest,' Captain Singh tweeted.
'Disturbing news of a blast at the @PunjabPoliceInd intelligence bureau building in Mohali. Praying for everyone's safety and well-being,' Punjab Congress chief Amrinder Singh Raja Warring tweeted.
'The bomb blast in Mohali is a sign of deep communalism,' stated former Punjab home minister Sukhjinder Singh Randhawa. 'I strongly condemn this incident and urge the @PunjabPoliceInd to investigate and take stern action against those who are intent on disturbing the peace of Punjab,' added Randhawa, the Congress MLA from Dera Baba Nanak.
'Deeply shocked at the blast at Punjab Police's Intelligence Bureau HQs, Mohali, exposing serious security lapses and highlighting once again the deteriorating law & order situation in Punjab. Thorough probe required to expose & punish those responsible,' tweeted Shiromani Akali Dal President Sukhbir Singh Badal.