Insurgents have launched pre-dawn attacks on a major Nato base in eastern Afghanistan and a nearby camp where seven CIA employees were killed last year in a suicide bombing.
Nato said there were no coalition casualties and the attacks were repelled.
It said 13 insurgents were killed - four of whom were wearing suicide vests - and five captured.
The assaults on the sprawling Forward Operating Base Salerno in Khost province and nearby Camp Chapman came just as area residents were rising for early morning prayers.
The area, about 60 miles south east of Kabul near the border with Pakistan, is a hotbed of activity by the Taliban and other insurgent groups, including the December attack on Chapman that killed four CIA officers and three contracted security guards.
Afghan police said about 50 insurgents attacked using rifles, heavy machine guns, rocket-propelled grenades and other weapons, but had been repelled.
Khost provincial police Chief Abdul Hakim Ishaqzai said they found the bodies of 14 militants outside Salerno and five others had been captured alive. He said police believed the bodies of more insurgents would be found.
After being driven away from the bases, the insurgents approached the nearby offices of the governor and provincial police headquarters but were driven off, Ishaqzai said.
"Given the size of the enemy's force, this could have been a major catastrophe for Khost. Luckily we prevented it," he said.
