Talks in South Africa on Zimbabwe's political crisis broke up Tuesday with no power-sharing deal between President Robert Mugabe and his bitter rival Morgan Tsvangirai in sight.

As negotiators flew home, South African President Thabo Mbeki, who is mediating the crisis, insisted discussions were still on track despite talk of a deadlock by Tsvangirai's opposition Movement for Democractic Change (MDC).

"They are adjourning for a number of days so that they could go back to Harare to consult with their principals and then come back," Mbeki told reporters in Pretoria, adding that talks would resume this week.

Tsvangirai flew to Johannesburg on Monday amid claims by his party that the talks had run into trouble.

Tsvangirai and 84-year-old Mugabe signed an accord on July 21 to begin talks on sharing power after a months-long election dispute.

The talks, which are being held at a secret location in the Pretoria area, are meant to be wrapped up within a fortnight of the signing of the initial framework agreement.

"It's going very well. In the memorandum of understanding they said they will try to conclude negotiations within two weeks.... They are very determined to keep to that commitment," said Mbeki.

Earlier, the chief spokesman for Tsvangirai's MDC was more downbeat and spoke of an impasse.

"The talks are in a deadlock. We cannot discuss the main issues, we can only say that they are in a deadlock and that the parties will consult with their principals," he said. "If the sticking points are resolved then the talks will resume," said George Sibotshiwe.

While Tsvangirai believes his victory in the first round of a presidential election in March should give him the right to the lion's share of power, MDC sources say Mugabe's negotiators are so far only offering him the chance to become a vice president.

"They have offered Morgan the post of third vice-president and nothing else, which is obviously a position totally unacceptable to the MDC," said one source.

There has been no comment so far from Mugabe's ruling ZANU-PF party, with neither of its chief negotiators, Justice Minister Patrick Chinamasa or Labour Minister Nicholas Goche, contactable.

Part of the agreement signed at a landmark meeting between Mugabe and Tsvangirai on July 21 was an undertaking to respect a media blackout during the course of the talks.

The meeting was their first since Tsvangirai formed his MDC at the end of 1999.

The former trade union leader has twice been charged with treason and needed hospital treatment for head injuries last year as he was assaulted by members of the security forces ahead of an anti-government rally.

The pair's bitterness hit new heights during the course of the election run-off when Tsvangirai was detained on five separate occasions while campaigning and his number two, Tendai Biti, was arrested for treason.

The MDC leader, who had not gained enough votes to win outright in the first poll in March, subsequently pulled out of the contest after dozens of his party's supporters were killed in attacks that he blamed on pro-Mugabe thugs.

Ignoring widespread calls to shelve the ballot, Mugabe went ahead and staged the poll, winning a predictable landslide victory.

Once seen as a post-colonial success story, the former British colony's economy has been in meltdown since Mugabe began a land reform programme at the turn of the decade and annual inflation now stands at some 2.2 million percent.

Unemployment is running at around 80 percent and even basics such as bread and cooking oil are scarce in the region's former breadbasket.