The U.S. military in Afghanistan says coalition and Afghan forces killed 15 militants during an operation in the southern province of Zabul.

A military statement Friday said troops were on their way to a local village in the Arghandab district to talk to elders about security issues when they were attacked by armed militants.  The forces killed one militant in that incident.

As the troops were searching a nearby compound, they came under attack again.  The military says the troops pursued the militants into a nearby cave complex, killing 14, and wounding 12 others.

In a separate incident, the Afghan Defense Ministry says three Afghan soldiers were killed early Friday during a clash with militants in eastern Kunar province.  Ministry spokesman Zahir Azimi said insurgents also suffered casualties but could not provide any figures.

Earlier this week, a top Taliban commander warned that militants are planning to unleash a new wave of ambushes, suicide attacks and bombings against international troops.

The U.S. is planning to send 21,000 additional troops to Afghanistan to deal with the country's growing insurgency.

Some information for this report was provided by AP and Reuters.