Zimbabwean opposition leader Morgan Tsvangirai charged Thursday that President Robert Mugabe and his long-ruling ZANU-PF party have resorted to coercion to press his Movement for Democratic Change to accept ZANU-PF's terms for a power-sharing government.

He issued the accusation after authorities at Harare International Airport seized his passports and those of several other MDC officials, preventing all but Secretary General Tendai Biti from leaving for Johannesburg and a summit of the Southern African Development Community which got under way Thursday with a meeting of SADC foreign ministers.

Negotiations between ZANU-PF and the MDC ground to a halt this week as Mr. Mugabe and Tsvangirai reached an impasse over their respective powers in a new government.

Correspondent Thomas Chiripasi was at the airport  Thursday and told reporter Ntungamili Nkomo of VOA's Studio 7 for Zimbabwe that authorities gave no reason for seizing the passports except to say there investigations they needed to carry out.

Security sources told VOA the directive to prevent Tsvangirai’s departure came from the Joint Operations Command which unifies the heads of the main uniformed and security services - and which some say has become the true seat of power in Harare in recent months.

Cabinet-level sources told VOA the JOC does not want to see a power-sharing agreement concluded between Mr. Mugabe and Tsvangirai.

SADC sources said regional leaders immediately put pressure on Harare, some threatening to boycott the summit, and convinced it to give back the passports and, as matters stood late Thursday, to allow the rest of the MDC delegation to leave Friday for Johannesburg.

Tsvangirai’s MDC formation meanwhile charged that ZANU-PF has approached more than 30 of its members elected to parliament in March elections offering them money and cabinet positions if they will agree to abandon Tsvangirai and join a new government.

Sources said all 10 members of parliament of the MDC formation led by Arthur Mutambara have also been approached. Mutambara on Wednesday disclaimed numerous reports saying he had reached a separate power-sharing with Mr. Mugabe.

President Thabo Mbeki, SADC's mediator in the Zimbabwe crisis since early 2007, is expected to brief the summit on the talks deadlock and seek the advice of his regional peers.

Tsvangirai told  reporter Blessing Zulu of VOA's Studio 7 for Zimbabwe that the seizure of the travel documents proved ZANU-PF is not negotiating in good faith.

Information Minister Sikhanyiso Ndlovu declined to explain why the authorities delayed Mr. Tsvangirai’s departure for Johannesburg and the SADC summit.

More reports from VOA's Studio 7 for Zimbabwe...