JOHANNESBURG, August 20, 2008 (AFP) - The Southern African region would miss Zambian President Levy Mwanawasa's 'invaluable contribution' to political and economic development, President Thabo Mbeki said Wednesday.

South Africa and the region were 'deeply saddened' by the Zambian leader's 'untimely' death Tuesday, said Mbeki.

'We must commit ourselves to building upon the foundations he laid as the chairperson of SADC...for the restoration and strengthening of regional political unity and cohesion,' he said in a statement.

Mwanawasa, who died aged 59 in a Paris hospital, was until recently chairman of the 14-nation Southern African Development Community (SADC). Mbeki only took over the chairmanship at the weekend.

Mwanawasa's legacy in deepening regional economic integration and infrastructure development should also be built on, said Mbeki.

Mwanawasa was one of the region's first leaders to speak out against Zimbabwe President Robert Mugabe, in contrast to Mbeki's long-standing quiet diplomacy approach to the worsening situation in the neighbouring state.

Mbeki is the SADC-appointed chief mediator in power-sharing talks between Mugabe and Zimbabwe's opposition.