The program is expected to double by the end of the year — and not a moment too soon, with nearly daily attacks since Friday killing five NATO troops, nine members of the Afghan security forces and an interpreter. In what was a symbolic victory for militants, a man in an Afghan army uniform penetrated to the heart of the Afghan Defense Ministry compound on Monday and gunned down two Afghan soldiers.

Militants hope to undermine trust between coalition and Afghan forces, who are increasingly partnered as the Afghans prepare to take the lead in securing the nation by the end of 2014. Last year, there were 10,400 partnered operations — up from 530 in 2009, the coalition said.

Convinced that insurgents were ramping up reconnaissance on security force movements, Afghan defense officials approached the U.S.-led coalition late last year and requested counterintelligence instruction for some of their top soldiers.