The operation, in the tribal region of South Waziristan, follows a skirmish a week earlier on the border with Afghanistan in which Pakistani soldiers killed eight suspected al-Qaeda members and arrested 18 others.

In the memo, Mr Rumsfeld says the record against al-Qaeda is mixed and suggests the US does not have the right mechanisms to know whether it is capturing, killing or deterring more terrorists than are being recruited.

The memo was originally circulated among the Pentagon's senior civilian and military leaders but reports of its contents later appeared in the USA Today newspaper.

Mr Rumsfeld said the memo was merely meant to provoke new thinking in the defence department.

In another development al-Jazeera journalist Tayseer al-Alouni, detained in Spain in September accused of having connections with al-Qaeda, is released on bail. Mr Alouni is the only journalist to have interviewed Osama Bin Laden since the 11 September terror attacks.

At least 35 people are killed and more than 200 injured when car bombs explode at the headquarters of the International Committee of the Red Cross (ICRC) and three Iraqi police stations.

Such tactics are often associated with "foreign elements", the chief British representative in the US-led administration, Jeremy Greenstock said.