Nato pulls out of Afghan ministries after Kabul attack
Nato said an "individual" had turned his gun on the officers, believed to be a colonel and major, and had not yet been identified or caught.
Nato commander Gen John Allen condemned the attack as "cowardly".
The shootings come amid five days of deadly protests over the burning of copies of the Koran by US soldiers.
Taliban statement
The interior ministry was put in lock-down after the shootings, officials said.
The BBC's Orla Guerin in Kabul says eight shots were reported inside the building, which should be one of the safest in the capital, and that any Afghan who carried out the attack would have had the highest clearance.
Local media reports said the gunman was an Afghan policeman but this has not been confirmed.
The reports suggest the incident followed a "verbal clash".
Gen Allen said he condemned the attack, adding: "We will pursue all leads to find the person responsible. The perpetrator of this attack is a coward whose actions will not go unanswered."
Details at http://www.bbc.co.uk/news/world-asia-17165410