KABUL, March 16 (Xinhua) -- At least 18 Taliban insurgents have been killed and 13 others injured in fresh clashes in Afghanistan, sources said on Friday.

In northern Kunduz province, two Taliban fighters were killed and three others wounded after the security forces repulsed attackers at a security checkpoint in Joy-e-Begum locality of Imam Sahib district Thursday night, bordering Tajikistan, district Governor Mahbub Sayyedi told Xinhua.

On Thursday, six Taliban militants were killed and four others wounded following airstrikes in Kajaki and Marja districts of southern Helmand province, the Afghan Defense Ministry said Friday.

The air raids also destroyed six narcotic drug labs together with a heroin-producing machine, the ministry said, without saying if the airstrikes were conducted by Afghan Air Force or NATO and U.S.-led coalition warplanes.

Helmand, notorious for poppy growing, is also a known Taliban stronghold.

In western restive Farah province, 10 Taliban militants were killed and six wounded after the Afghan army launched airstrikes and a cleanup operation in Bala Buluk district on Thursday, according to the Defense Ministry.

The province has been the scene of heavy clashes between Taliban and the Afghan security forces since January.

The Taliban insurgent group, which has been waging an insurgency for more than 16 years, has yet to make comments on the reports.