JALALABAD, Afghanistan, Sept. 12 (Xinhua) -- At least 70 civilians have been killed and over 250 others wounded in a suicide attack that targeted a peaceful rally in the eastern Afghan province of Nangarhar, an official said Wednesday.

The official, who declined to be identified, said that the terrorist disguised himself as a protester detonated his explosive device among the protesters, killing himself and 70 others.

According to the official, 258 others were wounded in the deadly suicide bombing on Tuesday.

Hundreds of people from Mohmandara district of Nangarhar province staged a rally on the main road linking the provincial capital Jalalabad to Torkham border town.

The peaceful protesters accused a local police officer of misusing power, calling upon the government to sack and punish him when the blast happened, the official added.

Meantime, spokesman for Nangarhar's provincial government Attaullah Khogiani told Xinhua that 68 people were killed and 165 others injured, saying more details would be available after completion of an investigation.

Local officials and people did not rule out the involvement of the hardliner Islamic State (IS) group in the carnage.

Neither the IS group nor the rival Taliban outfit has claimed responsibility for the deadly suicide bombing.

The UN Security Council on Tuesday condemned the attack in Afghanistan's Nangarhar province, which resulted in the killing of scores of people and injuring of many others.

Civilians usually bear the brunt of conflict in Afghanistan as 1,692 civilians had been killed and 3,430 others injured in the first half of this year, said a report of UN Assistance Mission in Afghanistan (UNAMA).