At least 50 Afghan civilians have been killed in separate incidents, as the West-backed Kabul government and Taliban fighters have stepped up attacks since a peace deal between the armed group and the US collapsed earlier this month, Aljazeera reports.

A US-backed air raid conducted by the Afghan security forces accidentally hit a farmland in Nangarhar province killing about 30 civilians and injuring 40 others, while at least 20 people were killed in Zabul province in a suicide car bomb claimed by the Taliban group.

Afghan officials said the drone attack on Wednesday night was aimed at destroying a hideout used by Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group fighters, but it accidentally targeted farmers near a field in Wazir Tangi area of Khogyani district in Nangarhar province.

Sohrab Qaderi, a provincial council member in Nangarhar said a drone strike killed 30 workers in a pine nut field and at least 40 others were injured.

The defence ministry in Kabul confirmed the strike, but refused to share casualty details immediately.

Attaullah Khogyani, a spokesman for the provincial governor of Nangarhar confirmed the air strike.

"The government is investigating the incident, so far nine bodies were collected from the attack site near a pine nut field," he said.

US forces were not immediately available for a comment.

Malik Rahat Gul, a tribal elder in Wazir Tangi said the air raid happened at a time when tired workers, mainly daily wage earners, had gathered near their tent after harvesting pine nuts in a field nearby.

"The workers had lit a bonfire and were sitting together when a drone targeted them," said Gul.

Earlier this month, four brothers were killed in a raid by the CIA-trained and funded 02 Unit of the National Directorate of Security (NDS) spy agency.