Zimbabwean authorities have briefly confiscated MDC opposition leader Morgan Tsvangirai's passport, threatening to prevent him attending a SADC summit in South Africa.
Mr Tsvangirai said he had been invited to attend the weekend summit, to be hosted by South African President Thabo Mbeki.
His departure was delayed when agents of Mugabe's Central Intelligence Organisation confiscated the emergency travel documents he was using, along with the passports of other MDC officials in his party.
Mr Tsvangirai has been using emergency travel documents after the authorities refused in June to renew his passport after it expired.
The travel documents were later returned without any explanation.
Earlier Mr Tsvangirai told reporters at Harare airport that negotiations cannot be judged on a deadlock over one issue.
Asked by reporters if he was still optimistic on a deal, Mr Tsvangirai said: 'Yes, of course, we got our independence after how many talks? Hundreds and tens of meetings had been held.'
