Several rockets have been fired at the Afghan capital, Kabul, where the meeting of the country's traditional grand assembly, or loya jirga, is winding up its proceedings.

One of the rockets hit a residential block, causing some damage but no casualties.

All three rockets landed near the American embassy and the headquarters of the International Security Assistance Force (Isaf), but a spokesperson for the force said it was unclear what the target had been.

French troops have been sent to the presumed launch site north-east of the capital's airport, where Afghan sources reported finding two unfired rockets after the attack.

International patrols

Isaf spokeswoman Lieutenant Colonel Helen Wildman said that an observation point at the airport reported seeing two rockets being launched at 2135 (1705 GMT).

German soldiers said the rockets were fired from the Qalai Zaman Khan district in the northern hills.

The rockets exploded within a kilometre of Isaf's headquarters, in the former Soviet compound off the central Jalalabad Road.

Lieutenant Colonel Wildman added that similar attacks on post-Taleban Kabul had happened before.

About 5,000 Isaf members have been patrolling Kabul since December and have stepped up security during the loya jirga.

Tuesday's blasts are the first such incident since the loya jirga opened on 11 June.