KABUL, Feb. 20 (Xinhua) -- The Afghan security forces have killed 28 militants in crackdown operations across the country, Defense Ministry spokesman Dawlat Waziri said on Tuesday.

The spokesman told a press conference that aggressive operations were going on in 12 of the country's 34 provinces and 28 militants had been killed over the past 24 hours.

The security forces were chasing and targeting militants in the restive areas of troubled provinces, including the militancy-plagued and poppy-growing Helmand province, Waziri said, adding that the operations backed by air power would last until the insurgents are killed or captured.

The Afghan soldiers have also discovered and defused 37 anti-personnel and anti-vehicle mines in the country over the past 24 hours.

Describing the ongoing operations against armed groups in the troubled areas of Nangarhar, Khost, Ghazni, Helmand, Herat, Zabul, Uruzgan, Farah, Takhar, Nimroz, Faryab and Laghman provinces as "successful" Waziri said the security forces would continue to target the "enemies" elsewhere in the country.

The government troops also raided a detention center of the Taliban insurgents in Alinegar district of the eastern Laghman province late Monday night and after killing eight rebels released 30 civilians "who were held there illegally," the Defense Ministry said in a statement.

Meanwhile, Taliban fighters have intensified activities and according to the outfit's sources, dozens of security personnel have been killed over the past two days in the conflict-hit Afghanistan.