Three NATO troops and at least eight people, including police officers, died in roadside bomb blasts on Tuesday, two days after the Taliban announced their fighting season.
A roadside explosion in southern Afghanistan killed at least three International Security Assistance (ISAF) members, NATO said.
An additional bomb in the southern province of Kandahar in the Shah Wali Kot district killed at least three civilians and wounded five, said Jawed Faisal, a provincial governor spokesman.
A third bomb in the northern province of Kunduz killed at least five people, including a police commander who had been known for reducing insurgent attacks in the area. Two of the five killed were officers traveling in the commander's car.
The news follows a cargo plane crash in Afghanistan that killed all seven US members of the crew on Monday. The cause of the deadly crash has not been determined. The Taliban claimed they shot down the plane, but a coalition statement said "Taliban's claims are false.''
On Sunday, the Taliban announced its annual spring offensive, proclaiming a "monumental spring operation" to defeat "this era's Western invaders."