Army Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, was consulting with senior U.S. and Afghan commanders and government officials just hours after another U.S. soldier was killed in a shooting, the Los Angeles Times reported.
Dempsey's visit came after two weeks of violence in which 10 U.S. soldiers were killed by Afghan security forces.
The attacks were "certainly among the topics of discussion" during the general's visit, a NATO official said.
Authorities in Kandahar province said the latest American death occurred Sunday when two Afghan policemen fired on a group of coalition and Afghan troops. Also killed was a police officer and one of the shooters, police said.
An Afghan interpreter was wounded. The second gunman escaped, police said.
The shootings have been referred to as green-on-blue or "insider" attacks.