A roadside bomb killed two NATO soldiers and wounded two others on patrol in eastern Afghanistan on Tuesday, the alliance said.

The roadside bomb struck the soldiers' vehicle in the province of Nuristan, NATO said. The two wounded soldiers were taken to a U.S. military facility in Asadabad in neighboring Kunar province.

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NATO did not release the nationalities of the soldiers, but U.S. troops are the primary NATO component in eastern Afghanistan.

NATO troops on Monday fought insurgents in southern Afghanistan for six hours in a firefight that left 55 militants and one NATO soldier dead. Another 20 militants were wounded in the battle in Zabul province, NATO said.

The nationality of the soldier killed Monday was not released, but many of the Western troops in Zabul are also American.

Afghanistan has seen a sharp rise in violence the last several months, particularly in the southern and eastern provinces near the border with Pakistan. Militants have been increasingly using roadside and suicide bombs in their attacks against Western and Afghan security forces.

In Ghazni province, meanwhile, a suicide attacker detonated himself Tuesday in the office of the chief of Andar district, killing one police officer and wounding another, said Gen. Abdul Ghafar, the provincial police chief.

Ghafar said the attacker tried to enter the chief's office but was stopped by the police.