By Greg Barrow BBC correspondent at the United Nations

A UN Security Council monitoring group has warned that the al-Qaeda movement may be converting its financial assets in an attempt to avoid global constraints on the funding of terrorist networks.

This new UN report paints a picture of al-Qaeda as a sophisticated organisation that may be adapting quickly to the new constraints placed on it since the attacks on Washington and New York, last September.

The monitoring group set up by the UN Security Council says it has been difficult for UN member states to target an organisation like al-Qaeda that consists of individuals and entities spread over a large geographical area.

And it says al-Qaeda may have changed the way it operates - the monitoring group says it is particularly concerned about the use of the internet by al-Qaeda to communicate and to execute financial transactions.

Arms flow

It says it is investigating allegations that al-Qaeda is diversifying its financial base by converting its assets into gold, diamonds and precious stones, with the aim of avoiding constraints that have been placed on more conventional financial systems, like banks.

The UN monitoring group also suggests that efforts to prevent arms from reaching al-Qaeda and Taleban fighters inside Afghanistan have not been entirely successful, as there appears to be no shortage of ammunition among those groups that remain in the country.

The monitoring group offers no new ideas about how to counter these problems and says the onus should be on UN member states to participate in and support international conventions aimed at suppressing the financing of terrorist groups and blocking the international trade in arms.