The leaders began their meeting shortly after the conclusion of a separate summit on an African free trade deal, and made no comments as they entered the meeting.

Leaders of the 15-nation Southern African Development Community met late Saturday on Zimbabwe and to review talks held earlier in the week on the crisis in Madagascar, but have given no indication of the substance of their discussions, expected to run into the night.

The region’s security “Troika” body in March issued a unusually sharp rebuke to Mugabe, demanding an end to political violence and insisting that reforms promised in the so-called Global Political Agreement are implemented.

That agreement created the unity government between Mugabe and his rival Morgan Tsvangirai, now the prime minister, after failed elections in 2008 ended in spiral of deadly political unrest and economic collapse.

Together they were meant to oversee the drafting of a new constitution and hold elections, but the process is running a year behind schedule, a delay that the Troika blamed on Mugabe during the March meeting in Livingstone.