Harare/Johannesburg - Zimbabwe's Electoral Commission (ZEC) said a runoff presidential election between President Robert Mugabe and opposition leader Morgan Tsvangirai would likely not take place within 21 days, as required by law, but within "the next 12 months," an African election observer said Wednesday.

Marwick Khumalo, head of the Pan-African Parliament observer mission to Zimbabwe's March 29 elections, said the election commission told him "logistical" issues would make it difficult to organize a runoff within three weeks of the election results.

The state-controlled ZEC released the results on May 2 after a more than month-long delay that stoked tensions in the southern African country. The results showed Tsvangirai taking 47.9 of the vote against 43.2 for Mugabe, with former finance minister Simba Makoni trailing a distant third.

In cases where no candidate gets more than 50 per cent of the vote the law calls for the two top vote-getters to enter a runoff.

ZEC told him the runoff would take place "at the earliest possible time," not "beyond the next 12 months," Khumalo told Pan-African parliamentarians meeting at Midrand in South Africa.

Khumalo himself said the climate of violence in Zimbabwe was "not conducive to a free and fair election."

ZEC's delaying of the results and its agreement to recount some the votes before the results were released showed it had "long lost control of the election process and its constitutional obligation has been gravely compromised," Khumalo said in a report on the polls.

His sentiments were echoed by the head of a regional election observer team.

"You cannot have the next round taking place in this atmosphere," Kingsley Mamabolo, head of the Southern African Development Community team of observers to the elections, said in Pretoria.

While warning against a hasty runoff, Khumalo said a political solution hashed out behind closed doors was also "dangerous."

Both Mugabe's party and Tsvangirai have talked of a unity government, but have disagreed on which of the two presidential candidates should lead it.

Meanwhile, Tsvangirai, who insists he won at least 50.3 per cent of the vote, has yet to announce whether he will participate in a runoff.

MDC sources say he will partake but only with assurances that the vote will be free and fair and that Mugabe supporters cease attacking opposition supporters for "voting wrongly."

The party says 25 of its members have been killed by youth militia loyal to Mugabe's Zanu-PF and members of the military since the elections, in what it calls a bid to pacify people into voting for Mugabe in a second round.

Zanu-PF has accused Tsvangirai's Movement for Democratic Change of attacking its members.

Rights groups have confirmed attacks on both sides but accuse Mugabe supporters of the far greater share of the violence.

A high-level delegation from South Africa, whose President Thabo Mbeki is southern Africa's appointed mediator in Zimbabwe, held meetings north of the border this week with all parties to the impasse. (dpa)