Morgan Tsvangirai, leader of the Zimbabwean opposition, was tonight under increasing pressure to sign a power-sharing deal with President Mugabe.

With Mr Mugabe and the leader of an opposition splinter group, Arthur Mutambara, in agreement, Mr Tsvangirai was urged by Mr Mutambara to “put national interest before self-interest".

Mr Tsvangirai walked out of negotiations yesterday claiming that the president was unwilling to cede enough of his authority to from a satisfactory coalition.

Reports last night suggested that Mr Mugabe had reached agreement with Mr Mutambara, who leads a separate faction of the Movement for Democratic Change, to exclude Mr Tsvangirai.

Mr Mutambara today denied any such agenda and called for all three parties to return to the negotiating table.

"This dialogue must not be allowed to crumble," he said. "All three parties must agree if there is to be an agreement. There is no way you can extract a bilateral agreement from a tripartite process."

"We are at a crossroads in our country. The leaders of our political parties must rise up to the challenge to provide leadership... [Mr Tsvangirai must] put national interest before self-interest."

If Mr Mutambara were to lead his faction of the MDC into a coalition with Zanu (PF) they would have a narrow majority in parliament of 109 seats to Mr Tsvangirai’s 100.

State media in Zimbabwe appear to be signalling that Mr Mugabe would go ahead and form a government, with or without Mr Tsvangirai.

Thabo Mbeki, the South African president, who is brokering the negotiations said today that talks were not yet over and agreement could still be reached.

"They need a bit of more time to reflect so they will do that," he said.

Mr Mbeki claimed there was only one key sticking point, which he refused to identify.

“We have dealt with all the elements on which President Mugabe and Mr Mutambara agree, but there is disagreement on one element over which Morgan Tsvangirai had asked for time to reflect,” he said. “We have adjourned to give Morgan Tsvangirai more time to consider these matters."

The international community in Africa and beyond is putting the three leaders under immense pressure to reach an agreement on sharing power after discredited elections earlier in the year.

Mr Tsvangirai claimed outright victory over the incumbent president in March elections, but the government rejected that claim and forced a second round run-off election for president.

The MDC leader pulled out of the June run-off saying it was too dangerous for supporters to vote against Zanu (PF).

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