KABUL — The three civilian police training contractors killed by an Afghan police officer over the weekend have been identified as two Americans and a British citizen, Afghan and NATO officials said Monday.

The shooting took place at a training academy in western Afghanistan, the officials said.

There were several other violent incidents around the country, some involving NATO forces, underlining the continuing volatility of Afghanistan as foreign forces prepare to wrap up their combat role by the end of 2014.

In one incident, a NATO service member was killed in an insurgent attack in eastern Afghanistan. No details were released, but the death brought the number of foreign forces killed this month to 33 and a total of 248 this year.

Also, NATO said two service members with the US-led coalition were wounded on Monday when an Afghan soldier opened fire on them in northern Afghanistan.

Four Afghan police were killed when a roadside bomb exploded next to their pickup truck in northern Baghlan Province, according to a deputy provincial police chief .

Sunday’s killing of the contractors occurred at a training academy. Afghan security forces or militants dressed in their uniforms have been killing a rising number of coalition forces, but they have not been specifically targeting civilian contractors working for the coalition. So far this year, 26 foreign troops have been killed in this type of attack.