Britain called Sunday for tough action as well as talk in the face of Zimbabwean President Robert Mugabe's defiance and signs of disunity among his opposition.

British Foreign Secretary David Miliband urged South Africa and the rest of the international community to "unite behind a tough, strong, clear (U.N.) Security Council resolution" calling for international sanctions against Mugabe.

Miliband spoke to reporters after visiting a downtown Johannesburg church that is a refuge for Zimbabweans fleeing their homeland's political and economic crises.

South Africa, though, has said the proposed resolution could undermine President Thabo Mbeki's attempt to mediate between Mugabe and Zimbabwean opposition leader Morgan Tsvangirai.

The U.S.-drafted resolution backed by Britain would require nations to freeze the financial assets of Mugabe and 11 of his officials, and to restrict their travel to within Zimbabwe.

Miliband said such targeted sanctions would spare the majority of Zimbabweans, already suffering in a collapsed economy, and could result in those closest to Mugabe pressuring him to yield at the negotiating table. Mugabe is accused of holding onto power through violence and fraud.

Miliband also said he supported Tsvangirai's calls for the African Union to appoint a mediator to work with Mbeki. Tsvangirai accuses the South African leader of siding with Mugabe, who has extolled Mbeki's role.

"There has got to be a clear mix of diplomacy and sanctions," Miliband said, adding that the suffering Zimbabweans described to him during his tour of the Central Methodist Church would spur anyone to try to find a solution.

"I've seen the human toll and the human face of the catastrophe," Miliband said.

Church officials say thousands of Zimbabweans have found a temporary haven at the church over the past four years, and the numbers coming have increased in recent weeks.

Around 2,000 Zimbabweans, double the usual number at any one time, were sheltering in the church's hallways, stairwells and storerooms Sunday. The main chapel has been kept clear for services, and some worshippers wearing their church best paused to greet Miliband.

Church officials said despair over the impasse in Zimbabwe was resulting in more people crossing the border. They also said Zimbabweans were heading downtown after fleeing areas elsewhere in South Africa where immigrants were attacked by poor South Africans who accused them of taking scarce jobs and housing _ an example of the far-reaching impact of Zimbabwe's troubles.

Mbeki made a brief, unannounced visit to Zimbabwe on Saturday. His spokesman, Mukoni Ratshitanga, said Mbeki met with Mugabe and Arthur Mutambara, leader of a small faction of Tsvangirai's party, but not with Tsvangirai.

Mutambara's meeting with Mbeki could signal dissension within the opposition, complicating already dim prospects for the success of mediation. Continued...