Obama deeply concerned over Afghan "insider attacks"

President Barack Obama

on Monday said the United States needed to do more to safeguard U.S. troops after a spate of Afghan "insider" attacks that have left 10 American troops killed in the past two weeks. His comments came during a visit by the top U.S. military officer, General Martin Dempsey, to Afghanistan, where the killings of American forces by Afghans have topped the agenda. Obama, who spoke to Dempsey earlier in the day, said he would reach out to Afghan President Hamid Karzai about the killings. "We've been watching with deep concern these so-called green-on-blue attacks, where you have Afghan individuals, some of whom are actually enrolled in the Afghan military, ... attacking coalition forces," Obama said. There have been 32 insider attacks so far this year involving 36 shooters that have led to 40 coalition deaths, just over half of them Americans. Some 69 coalition troops have been wounded. That's a sharp increase from 2011, when 35 coalition troops killed, 24 of whom were U.S. troops during the year. The growing insider threat has eroded trust between NATO and its Afghan allies, causing a headache for Western powers who are planning to pull out most of their troops by the end of 2014. After noting some of the steps to bolster protection of U.S. forces, Obama said: "Obviously, we're gonna have to do more, because there has been an uptick" in the number of attacks. "I'll be reaching out to President Karzai as well because we've got to make sure that we're on top of this," Obama said. Over the weekend, U.S. Defense Secretary Leon Panetta and Afghan President Hamid Karzai spoke by phone and agreed to boost vetting of Afghan recruits to try to put an end to the spiraling attacks, now averaging one a week. In Kabul, Dempsey met with his Afghan counterpart, General Sher Mohammad Karimi, who raised the issue of insider threat at the start of their meeting -- something Dempsey saw as a sign of Afghan resolve. "In the past, it's been us pushing on them to make sure they do more," he said. "This time, without prompting, when I met General Karimi, he started with a conversation about insider attacks - and, importantly, insider attacks not just against us, but insider attacks against the Afghans, too," in comments provided by his spokesman from Kabul. Reclusive Afghan Taliban leader Mullah Mohammad Omar has said insurgent fighters have successfully infiltrated the Afghan security forces. In a statement released last week, he urged police, soldiers and government workers to "abandon support of the invaders" and back the Taliban ahead of the departure of most Western combat troops in 2014. Still, last week, the Pentagon said only about 11 percent of so-called "insider attacks" by Afghans against NATO troops this year were due to Taliban infiltration, with the vast majority due to other motives, including personal grudges. Why there would be a sudden increase in personal grudges and other vendettas remains unclear.