At least 43 Taliban militants were killed as Afghan security forces mounted an operation in the country's Kunduz province, authorities said on Sunday."Joint Afghan security forces backed by army's air power also injured 14 militants in Khan Abad, Ali Abad and Imam Sahib districts during an ongoing operation codenamed 'Thunder 14' on Saturday," Xinhua news agency cited an army statement as saying.The Taliban on Saturday seized Khan Abad but the security forces regained control of the strategic district which is located 25 km east of the provincial capital Kunduz city."Taliban district governor Hussain from Khan Abad was also killed," the statement said.Sporadic clashes were going on in the militancy-hit province, sources said.Kunduz and neighbouring Baghlan and Takhar provinces have been the scene of heavy clashes over the past couple of months as Taliban has been trying to challenge the government forces in the once relatively peaceful region.