An altercation at the Afghan Interior Ministry has led to the deaths of two US advisers, officials say.

They said the service members were shot dead by another Westerner inside a room used only by foreign advisers.

The Interior Ministry issued a statement saying that two of the ministry's international colleagues had been killed, and an investigation was under way.

Nato confirmed that two of its service members had been killed in the capital, Kabul, but gave no other details.

The shooting comes on the fifth day of protests across the nation sparked by the burning of Korans at a US base.