KABUL, Afghanistan (CNN) -- One Swedish soldier with the NATO-led mission in Afghanistan was killed and three others were wounded, including one critically, in a bomb attack on their vehicle, the Swedish Defense Ministry said Saturday.

The soldier died early Saturday at a hospital in Kabul that is run by the International Security Assistance Force, the NATO peacekeeping force in Afghanistan.

Another soldier remained in critical condition at that hospital, and two others were in stable condition at a separate facility, the ministry said.

The attack happened around 3:40 p.m. (11:10 a.m. GMT) Friday when a roadside bomb detonated near their vehicle on the outskirts of the city of Mazar-e-Sharif, in northern Afghanistan, according to the ministry.

The two most seriously wounded were flown to the hospital in Kabul for treatment.

An investigation into the explosion has been launched, and the Afghan National Police have been cooperating in that effort, the ministry said.

Sweden has about 85 troops participating in the roughly 10,000-member ISAF force, mainly participating in reconstruction efforts in the Mazar-e-Sharif area.