A rocket has struck the headquarters compound of United Nations peacekeepers in Kabul, Afghan police said.
The terror threat is ever present in Afghanistan
UN officials confirmed that an explosion had occurred in the International Security Assistance Force (Isaf) compound which is situated near the United States Embassy, but there were no casualties.
A second rocket fired at the same time, 2240 (1810 GMT) on Sunday, hit a residential area in the south-east of the city but also caused no injury, Afghan government officials said.
The attack comes a day after two US special forces soldiers - operating separately from the Isaf troops - were killed in an ambush in the south-western province of Helmand.
Armoured vehicles from Isaf, which has military bases around the city, arrived along with Afghan police vehicles outside the compound after the blast to secure the area.
An Isaf spokesman said the blast had damaged an accommodation block and that it was the first time the compound had been hit directly.
But two rockets struck one of the force's bases in the city on 10 February.
Militants loyal to the former regime, renegade warlords or al-Qaeda have been blamed for frequent attacks on government and UN facilities in Afghanistan.
The 4,700-strong Isaf contingent performs a largely policing role in Kabul while a separate, US-led force of about 11,500 service personnel is hunting down suspected militants across Afghanistan as a whole.