The top UN official for the Central African Republic, Margaret Vogt, said the ceasefire agreement, witnessed by the regional groupingEconomic Community of Central African States (ECCAS) - was to come into force within 72 hours of being signed.
Diplomats expect some 3, 300 troops from seven or eight countries belonging to the regional grouping known as ECOWAS (the Economic Community Of West African States) to arrive in Mali over the next week or so.
The UK's economic power also means it is a member of the Group of 8 countries (G8), originally a grouping of the world's seven richest industrial democracies.