There have been conflicting reports about whether Afghan police or Norwegian troops might have been responsible for the casualties.
At least 15 others were reported injured in the clash in the town of Maymana. Two international troops also sustained injuries from shrapnel, according to a squadron leader from NATO's International Security Assistance Force (ISAF).
Afghan officials say the demonstrators were trying to storm a complex housing NATO troops with guns and grenades.
A NATO spokesperson has confirmed that ISAF troops fired teargas at the crowd after the mob began throwing stones.
Two ISAF soldiers were wounded by shrapnel during the incident, Squadron Leader Annie Gibson-Sexton said in the capital Kabul. She could not confirm their nationality or reports from Oslo that five Norwegians and two Finns had been wounded.
Two Boeing planes brought ISAF reinforcements to the city and the situation was brought under control by late afternoon, according to a deputy provincial governor.
The United Nations announced that all nonessential staff was being evacuated from the town.
The caricatures, which Muslims say are blasphemous, first appeared in a Danish newspaper and have been reprinted in several European publications, including in Norway.
(AP, Reuters, AFP)