The NATO-led force in Afghanistan says a man wearing an Afghan police uniform has shot and killed a NATO service member in the country.

The coalition said it was investigating Thursday's incident. It is unclear if the shooter was actually a police officer or just disguised as one.

NATO said another service member was killed in an insurgent attack Thursday in eastern Afghanistan.

Violence in the country has increased as Afghans begin taking security control from U.S. and NATO-led forces. Most foreign combat troops are set to leave Afghanistan by the end of 2014.

In a separate incident Thursday, a bomb attack in the country's north killed an Afghan intelligence official.

The victim worked in the Kunduz city branch of Afghanistan's National Directorate of Security. Authorities say the blast destroyed the official's car. The explosion also wounded three children.

The attack comes two days after suicide bombers attacked a compound that houses private security companies in Kunduz, killing at least four Afghan security guards.

The Taliban claimed responsibility for that attack, the first major strike by insurgents in Afghanistan since the beginning of the Muslim holy month of Ramadan.