An Afghan National Army (ANA) soldier keeps watch at the gate of British-run military training academy Camp Qargha, in Kabul. Reuters

An insider attack on high-level officials at the British-run Camp Qargha has killed a two-star American Major General, the highest-ranking US citizen to die in the Afghanistan war thus far.

A lone gunman, dressed as an Afghan soldier, opened fire on the visiting officials at close range during a meeting at the Marshal Fahim National Defence University, part of the military complex, in Kabul.

The Nato-led International Security Assistance Force (Isaf) confirmed one of its members had been killed in the "incident" and were investigating the circumstances.

Coalition officials, who spoke on condition of anonymity and would not release the name of the major general, said an unspecified number of other service members of the American-led coalition and Afghan soldiers, including a senior Afghan commander and German Brigadier-General, were also shot. Their conditions were not immediately known.

A US official said that "about a dozen" of the 15 wounded in the attack were Americans. An Afghan commander was also injured.

The Afghan Defence Ministry said in a statement that a "few people were wounded" in the incident and had been evacuated to a hospital. It said that the assailant was "wearing Afghan National Army uniform".

Tensions were said to be running high following the shooting as foreign troops become more wary of "insider attacks" from Afghan soldiers.

The base is an Afghan army facility west of Kabul which trains officers for the army and is known as "Sandhurst in the Sand" because of its similarities to the famous British military academy.

This is another case of an "insider attack", common incidents in Afghanistan where domestic troops turn their back on their international partners because of various grievances, including resentment at the international presence in the country.

The Taliban occasionally claims the attacks as evidence that it has infiltrated the foreign presence in the country.