Unknown persons on Monday threw a grenade near the Indian Army’s gate near Pathankot’s Dheerapul in Punjab when a marriage procession was passing through the area, ANI reported. All police checkposts in the Punjabi city have been put on alert.

No injuries were reported because of the blast. The local police officials recovered parts of the grenade from the site.

The police have described the incident as a “terror attack” and registered a case under sections of the Explosives Act, reported PTI.

“Local police, counter intelligence and CID [Crime Investigation Department] are working together,” Inspector General of Police (counter intelligence) Gulneet Singh Khurana said, according to ANI. “No arrests [have been] made yet, we are collecting evidence and will take action based on the facts. If a grenade has been hurled then there must be some terror angle, we are probing.”

“Further investigation is underway,” said Senior Superintendent of Police Surendra Lamba. “CCTV footage will be probed.”

The police have intensified checking vehicles at various points in and around the district. The Army and police have also conducted a search operation using a drone near the border area after some villagers claimed to have seen suspicious looking people on Sunday.

The Indian Air Force’s base in Pathankot was attacked on January 2, 2016, by six terrorists from Pakistan. They had entered the country through Punjab’s Kathua-Gurdaspur border.

The gunfight between the terrorists and the security forces continued for three days. All the terrorists and seven soldiers were killed in the operation. The Hizbul Mujahideen had claimed responsibility for the attacks.