The top U.S. military officer is in Afghanistan to meet with NATO and Afghan officers about the recent wave of attacks by Afghan soldiers and police against international forces.

Army General Martin Dempsey, the chairman of the Joint Chiefs of Staff, landed at Bagram Air Field outside Kabul Monday.

Afghan security forces have killed 10 international troops in the past two weeks. In the latest incident Sunday, a person wearing an Afghan police uniform shot and killed a NATO service member. At least 39 international coalition members have been killed in insider attacks this year.

NATO troops have been ordered to carry loaded weapons at all times, even when on their bases, as a precaution against the attacks.

The Taliban says it has infiltrated the ranks of Afghan security forces and considers the attacks a major part of its strategy against alliance forces.

U.S. Defense Secretary Leon Panetta discussed the issue of insider attacks with Afghan President Hamid Karzai in a phone call Sunday. The Defense Department said Panetta urged Mr. Karzai to boost counterintelligence cooperation with NATO, introduce more rigorous vetting of Afghan security recruits and engage in more dialogue with village elders who can vouch for such recruits.

The Pentagon said Mr. Karzai and Panetta agreed that U.S. and Afghan officials should work more closely together to minimize the potential for future attacks.