According to authorities, a massive explosion inside a court building in Ludhiana, a city in northern India's Punjab state, killed at least two persons and injured two more.

According to broadcaster NDTV, Thursday's blast damaged the walls of a toilet at the judicial complex and shattered glass in other rooms.

Police officers brought the injured out of the building in video footage released online. Additionally, officers were spotted requesting that people vacate the premises and evacuate the area.

The explosion's cause was not immediately determined.

Charanjit Singh Channi, Punjab's chief minister, declared the government "on alert" and announced an investigation.

Channi also expressed his sadness over the explosion in a Twitter tweet, stating that he was going to the scene.

"I assure the state's citizens that the guilty will not escape," he added.

"Anyone attempting to disrupt the state's peace and harmony will be prosecuted."