The British museum is to come under renewed pressure to give up leading treasures as 16 countries plan to sign a declaration that demands the return of artefacts sent overseas generations ago.

The demand, issued in Cairo at the end of a two-day conference, is addressed to every country that holds ancient relics.

Western museum hold most of the items listed by countries ranging from China to Mexico. The British museum is the principal target because of the prominence of the artefacts it owns.

Egypt wants returned include the Rosetta stone in the British Museum and the bust of Nefertiti in Berlin's Neues Museum. Both the British and Neues Museum have rejected the demand.

The conference was hosted by Zahi Hawass, the head of Egypt's Supreme Council of Antiquities, who has been an outspoken campaigner for the return of lost treasures.

Mr Hawass acknowledged that there was no international legal basis for the demands but said a united stand between affected nations would bolster the claims.