The pressure on Robert Mugabe and ZANU-PF to end their brutal campaign against the opposition and innocent civilians intensified on Friday, when a group of 40 prominent African leaders and influential celebrities issued an open letter calling for an end to violence and intimidation, ahead of the presidential run-off elections on June 27.

The impressive list includes many respected former heads of state, including Mozambique's Joaquim Chissano and Botswana's Festus Mogae, musicians and UNICEF Goodwill Ambassadors Youssou N'Dour and Angelique Kidjo, Nobel Laureate and Chairman of The Elders Desmond Tutu, and former United Nations Secretary-Generals Boutros Boutros-Ghali and Kofi Annan.

The African leaders urged the Zimbabwe government to end the violent campaign that has gripped the country since the March 29th elections, when the ruling party lost their parliamentary majority for the first time ever. They also called for the full resumption of field operations by humanitarian aid groups that were suspended by government last week.

Their appeal falls well in line with previous calls by African leaders for 'an African solution to African problems' because all the signatories are African. Notably, none of the current African heads of state are included. Many of them have maintained a deafening silence on the Zimbabwe crisis.

Anglican Bishop Rubin Phillip in South Africa said he was immediately supportive of the initiative when he learned of it. He called it a commendable, non-violent approach that publicises the widespread abuse that is taking place in Zimbabwe. He added that it also sends a strong message to the Zimbabwe government that the world will not tolerate what they are doing.

However, Bishop Phillip believes that what is needed are the voices of current African leaders. He said: "It is alarming that they are silent in the face of all the abuses in Zimbabwe. If they do not speak it is as though they are supportive of what is happening there."

"Whatever the outcome of the election, it will be vital for all Zimbabweans to come together in a spirit of reconciliation to secure Zimbabwe's future. We further call upon African leaders at all levels - pan-African, regional and national - and their institutions to ensure the achievement of these objectives." the letter said.

The government of Botswana also spoke out strongly on Friday. A statement form Botswana's Ministry of Foreign Affairs and International Cooperation said they had summoned the Zimbabwean Ambassador Thomas Mandigora on Thursday, to express strong concern over the latest arrests and detentions of MDC leaders Morgan Tsvangirai and his Secretary General Tendai Biti.

The statement said: "The repeated arrests and detentions are unacceptable and deserve condemnation as they violate the Principles and Objectives of the SADC Treaty."