Opposition parties in Punjab on Tuesday condemned an attack on the intelligence wing headquarters of the state police in Mohali and asked Chief Minister Bhagwant Mann to set his priorities right and focus on the serious challenges confronting the state.

A rocket-propelled grenade (RPG) was fired at the third floor of the highly-guarded building on Monday night. No one was injured in the incident.

A high alert has been sounded in Punjab and police are carrying out vehicle checking at several places across the state.

Reacting to the incident, Punjab Congress chief Amrinder Singh Raja Warring asked the chief minister to set his priorities right and focus on the serious challenges confronting the state.

"Inexperience and misplaced priorities of the Aam Aadmi Party government are being exploited by terrorists who seem to be raising their heads in Punjab," he said in a statement.

Warring said this was an attack on Punjab by the enemies of peace and integrity, which can and will be defeated by working together.

Former chief minister Amarinder Singh reiterated that Punjab is under a continuous threat from forces inimical to the country's unity and integrity and called for unified, coordinated and strong efforts to nip the threat in the bud.

Reacting to the Mohali incident, Singh said it was part of a series of recent developments like seizure of RDX, drugs sent through drones and arrest of a few suspects.

He warned against the designs of Pakistani spy agency ISI, saying it has never given up its intentions about Punjab and will always seize any opportunity that it gets.

In a statement, Singh expressed concern over the ISI managing to rope in criminals and gangsters for subversive activities in the state. He said there is a possibility of more weapons having landed in Punjab and more people getting involved, who need to be identified.

He also cautioned against the "inexperience" of the new government in the state and urged it to coordinate with the Centre and various security agencies.

"The state government should go to any extent and seek support and cooperation of everyone to save Punjab," Singh said, while observing that "Punjab cannot afford another phase of turmoil after having paid a heavy price earlier".

Bharatiya Janata Party (BJP) national general secretary Tarun Chugh said the "grave laxity" in surveillance under the AAP government has "exposed Punjab once again to the threat of revival of militancy".

"It is time Chief Minister Bhagwant Mann stopped playing second fiddle to Delhi Chief Minister Arvind Kejriwal and campaigning for him in other states, leaving Punjab in the hands of lawless forces," Chugh said in a statement.

Congress leader Navjot Singh Sidhu sought exemplary punishment for those behind the incident. The cricketer-turned-politician also said the attack showed state intelligence in poor light.

"The attack on Intelligence office in Mohali goes to show state intelligence in very poor light.... Wake up call for Govt. Eternal vigilance need of the hour, Law and order top notch priority! Prevent and prepare rather than repent and repair.... Exemplary punishment for the perpetrators....," the former Punjab Congress chief said in a tweet.

Congress MLA and Leader of Opposition in the Assembly Partap Singh Bajwa said the attack on the intelligence headquarters is worrying, adding that any damage to the state's hard-earned peace cannot be afforded.

"RPG attack on Punjab Police intelligence wing office in Mohali is worrying. This after RDX was found few days back in Tarn Taran. Punjab has been through dark times already, we can't afford to damage the hard earned peace of Punjab," Bajwa said in a tweet.