A suicide bomber attacked a convoy of foreign soldiers in the Afghan capital, Kabul, on Saturday, a police official said, but there was no immediate word on casualties.

A suicide bomber attacked a convoy of foreign troops but there are no details about casualties yet, said Hashmat Stanekzai, a spokesman for the Kabul police chief.

There was no immediate comment from the NATO-led International Security Assistance Force (ISAF).

The attack took place in the Darulaman area in the west of the city, near the national museum. The former royal palace, now in ruins, is also in the area, along with several government departments.

Violence across Afghanistan is at its worst since the start of the war 10 years ago, according to the United Nations, despite the presence of more than 130,000 foreign troops.

ISAF says there has recently been a fall in attacks by insurgents but this data excludes attacks that kill only civilians and attacks on Afghan security forces operating without international troops.

On Thursday, insurgents armed with rifles and rocket-propelled grenades attacked two bases used by foreign troops in southern Afghanistan. An Afghan interpreter working for ISAF was killed in that attack, which stretched into Friday before the last of the four insurgents were killed.

There has been a series of high-profile assassinations, as well as day-to-day attacks by Taliban raiders, over the past year.

In the most spectacular recent attack, insurgents launched a 20-hour assault on the U.S. embassy and ISAF headquarters in Kabul in September. More than a dozen people were killed in that assault.

(Reporting by Hamid Shalizi; Writing by Daniel Magnowski; Editing by Paul Tait)