They are also potentially embarrassing for U.S. President Barack Obama’s administration, which has spent billions of dollars training Afghan troops as Washington seeks to extricate itself from the costly, 15-year-old war. The disclosure could fuel criticism by supporters of Republican presidential nominee Donald Trump, who has accused the Obama administration of failing to properly vet immigrants from Muslim-majority countries and has pledged a much tougher stance if he wins. While other foreign troops on U.S. military training visits have sometimes run away, a U.S. defence official said that the frequency of Afghan troops going missing was concerning and “out of the ordinary.”Since September alone, eight Afghan troops have left military bases without authorization, Pentagon spokesman Adam Stump told Reuters. He said the total number of Afghan troops who have gone missing since January 2015 is 44, a number that has not previously been disclosed. “The Defense Department is assessing ways to strengthen eligibility criteria for training in ways that will reduce the likelihood of an individual Afghan willingly absconding from training in the U.S. and going AWOL (absent without leave),” Stump said.