Johannesburg- Zimbabwean President Robert Mugabe was holding talks with his Zanu-PF party on Friday, amid speculation about a possible run-off presidential election that would pit him against opposition leader Morgan Tsvangirai.

The 84-year-old leader was attending a crucial meeting of his Zanu-PF's politburo (inner circle), expected to discuss the party's options following last weekend's presidential, parliamentary and local elections.

Zanu-PF was defeated by Tsvangirai's Movement for Democratic Change (MDC), which won 109 seats in the 210-seat House of Assembly (lower house of parliament), compared to 97 seats for Zanu-PF.

Six days after the polls, the official results of the most closely-watched race, the presidential vote, had yet to be announced but a second round between Mugabe and Tsvangirai looked a strong possibility.

The MDC has declared a run-off unnecessary, claiming Tsvangirai to be the outright winner based on its own vote count. However, the party has also said it would participate - "under protest" - in a run-off.

Mugabe's deputy information minister Bright Matonga appeared to pave the way for a run-off Thursday, saying Mugabe would "fight to the last."

The standoff was expected to dominate talks in London between South African President Thabo Mbeki and British Prime Minister Gordon Brown.

The two leaders were to meet Friday ahead of Saturday's Progressive Governance summit. Mbeki, who said he held talks with Tsvangirai, echoed several world leaders in calling on Zimbabwe's leaders to respect the election outcome, whatever it produced.

With tensions mounting by the inexorable wait for the presidential results, the MDC accused Mugabe of preparing a crackdown on the opposition.

"They are preparing for a war," MDC secretary general Tendai Biti said in radio and television interviews, urging the international community, including Mbeki, to be on the watch for a spike in state-sponsored violence.

"We are desperately worried about violence," said David Coltart, a lawyer and winning senator from a smaller MDC faction led by Arthur Mutambara that had been backing former finance minister Simba Makoni for president.

"The opposition will unite behind Morgan Tsvangirai" (in the event of a runoff)," Coltart said in a BBC interview.

In a first sign of a clampdown on Thursday, police arrested two foreign journalists, New York Times reporter Barry Bearak and Stephen Bevan of Britain's Daily Telegraph, and unidentified intruders ransacked a hotel room used by the MDC to "look for documents."

The two journalists were charged with violating Zimbabwe's media laws. A US employee with a Washington-based think-thank, the National Democratic Institute, was also being held.

In further signs of a possible crackdown, sources in the northern town of Bindura told Deutsche Presse-Agentur dpa that members of Zanu-PF's youth militia were mobilizing and a column of about 400 young men marched through Harare with a police escort.

As momentum for a run-off appeared to be building, the MDC alleged Mugabe was preparing to change the law to allow a run-off within 90 days, instead of 21 days as currently called for by law.

"He would be ruling illegally because his term expired on March 28 (the day before elections)," Biti accused.

With no sign of the presidential results a few hours before a six-day legal deadline for their release, the MDC launched a High Court application to force the Zimbabwe Electoral Commission to hurry their announcement.

A seemingly unperturbed ZEC, however, was busying itself with results from the 60-seat Senate election.

With 10 seats announced Mugabe's Zanu-PF party and the MDC were neck and neck with 5 seats each. (dpa)