Police rearrested Morgan Tsvangirai, the Zimbabwean opposition leader, on Wednesday sparking rare criticism from a senior South African official just as regional leaders were due to meet to discuss Zimbabwe’s escalating crisis.

The raid by armed police on the opposition Movement For Democratic Change (MDC) offices in Harare was carried out only hours before President Robert Mugabe flew out to Tanzania for an emergency summit of the 14-nation Southern African Development Community (SADC). Zimbabwe’s deteriorating political and economic environment was set to be top of the agenda at the meeting.