KABUL, Afghanistan -- Insurgents pulled four Afghan civilians off a minibus travelling in the east of the country, shot them dead and left their bodies on the side of the road, officials said Wednesday.

Also, four NATO service members died in attacks.

The new violence underscored the security dangers in the country as NATO works toward handing over responsibility to local forces by the end of 2014.

Villagers reported Tuesday's minibus attack in Jalrez district to police, who then recovered the bodies, said Wardak provincial government spokesman Shahidullah Shahid. It was the second such shooting in the district in two weeks. Last week, four Afghan security guards were pulled out of a vehicle and killed in the same way, execution-style.

Civilians have borne the brunt of the violence from the long-running Afghan conflict.

According to the United Nations, last year was the deadliest on record for civilians in the Afghan war, with 3,021 killed. The number of civilian deaths dropped 36 per cent in the first four months of this year compared with last year, but the U.N. says much of that is probably tied to a particularly severe winter that decreased fighting overall.

Four NATO service members were killed in attacks across the country on Wednesday. Two died in separate bomb blasts in the south and two others in a bombing in the east, the international military coalition said. NATO did not provide the nationality of the dead nor any other details on the attacks.

Last month, 45 international service members were killed in Afghanistan, compared to 52 killed in July of 2011.

Also, an Afghan district police chief was killed in the southern province of Zabul along with two of his bodyguards when their vehicle struck a roadside bomb around midday, said Mohammad Jan Rasoolyar, the provincial deputy governor. It was unclear if the police chief was the intended target.