The Swedish-Finnish patrol was operating on the main road from Mazar-e-Sharif and Sheberghan when their came under attack.
"The injured first received help from their colleagues and were then transported by US ambulance helicopter to the German military hospital in Marmal," the statement said.
The attack took place 45 kilometres west of Mazar-e-Sharif in northern Afghanistan, where the Swedish troops are stationed. The weapon used in the attack was an rocket-propelled grenade launcher (RPG).
Reinforcement in the form of air and ground units were sent to the location.
The injured Swedish officer is reported to be from Norrbotten in the north of Sweden and his close relatives have been informed.
Sweden has around 500 troops in Afghanistan. Thus far five Swedish soldiers have died, as well as a Norwegian with dual Swedish citizenship, and an Afghan interpreter employed by the Swedish forces.