At least four people were injured in a crude bomb explosion during a rally of  National Citizen Party (NCP) in Savar on Monday night.

The explosion occurred around 9:45 pm at the Eidgah ground near Enam Medical College Hospital in Savar municipality while an NCP rally was underway following the party's "July March" programme, said witnesses.

They said panic spread among party leaders, activists and spectators after a loud explosion ripped through the rally venue.

The injured were identified as Shahin Khandaker, 30, Jasim, 26, Shahadat Hossain, 40, and Imran, 35.

The condition of Shahin and Jasim was reported to be critical.

NCP central committee member Yasir Arafat said miscreants hurled the crude bomb while Dhaka district NCP Convener Engineer Nabila Tasnid was delivering her speech.

NCP Convener Nahid Islam, Member Secretary Akhtar Hossain and Chief Organiser (Northern Region) Sarjis Alam were among the party leaders present on the stage during the incident.

Following the blast, Nahid Islam led party leaders and activists to Savar Police Station, where they staged a demonstration.

He later told reporters that several party leaders and activists have been injured in the attack.

Nahid alleged that the attack was carried out by "terrorists linked to the government and the Awami League."

He also claimed that members of an organisation which is facing ban on activities are carrying out flash processions without effective action from the authorities .

Officer-in-Charge (Investigation) of Savar Police Station Nur Mohammad said law enforcement personnel rushed to the scene after the explosion, brought the situation under control and launched an investigation.

He said the NCP has filed a complaint with the police station over the incident.