National Citizen Party (NCP) Convener Nahid Islam on Monday accused the police of failing to protect his party's leaders and activists during the bomb attack on its rally in Savar, saying the force must prove its neutrality by arresting those responsible.

Speaking to journalists in front of Savar Police Station, Nahid said an attack of this nature reflected "a failure of the police and law enforcement agencies" and alleged that political motives lay behind the incident.

"If the police are politicised, they will not be able to protect us because they will act on political instructions," he said. "If the police can make arrests now, then we will know they are working impartially."

Nahid said police had claimed they had intended to prevent the attack but failed. According to him, whether the perpetrators are arrested will demonstrate "how capable the police really are of ensuring security in Bangladesh."

He said police officers were present at the venue before the attack but appeared inactive after the power supply was cut. "After the bomb attack, some police officers came and tried to protect us. Others left," he said.

"We want to see action, not words. If they are serious about ensuring justice, arresting the terrorists and guaranteeing the safety of the people of Savar, they must prove it through arrests."

Nahid said the party had so far received reports of two people being injured in the attack. He said NCP leaders would visit the injured at the hospital and vowed that the party's July March campaign would continue despite the violence.

"Our July March will continue. No matter what happens, it will go on," he said.