HARARE - Zimbabwe's opposition on Saturday held out the possibility its leader would face President Robert Mugabe in a presidential run-off, but called on the country's neighbours to verify the vote count from the first round.

Thokozani Khupe, vice-president of the Movement for Democratic Change, said the group still believed a run-off was unnecessary, maintaining opposition leader Morgan Tsvangirai won the first round outright on March 29.

The Zimbabwe Electoral Commission released results a day earlier giving Tsvangirai the lead, but not the simple majority needed to avoid a run-off with Mugabe, the second-place finisher. The opposition rejected those results as fraudulent.

At a news conference Saturday, Khupe called on the Southern African Development Committee to help verify the results.

"We still need to be convinced before we participate in a run-off,'' she said.

Top opposition leaders were expected to meet this weekend to consider their next step. Khupe did not comment on the meeting.

No run-off date has been set. Deputy Information Minister Bright Matonga said the constitution requires a second round no sooner than 21 days from the announcement of the results and no later than a year.

The opposition has consistently rejected a run-off, but its stance has appeared to soften since the official results were released, and Mugabe's party said he would take part in a second round.

On Friday, Tsvangirai's deputy in the Movement for Democratic Change, Tendai Biti, acknowledged that skipping a second round could result in another term for Mugabe. Biti told reporters in Johannesburg in neighbouring South Africa that the only way out of the impasse was a power-sharing government led by Tsvangirai, but with no role for Mugabe.

Biti also said a run-off would be illegal and there could not be one "for the simple and good reasons that that country is burning'' amid violence and an economic collapse from rampant inflation.

International observers have questioned whether a run-off would be legitimate, given the violence the opposition has faced. The opposition's top leaders, including Biti and Tsvangirai, have been staying out of Zimbabwe for fear of arrest.

In a statement Friday, New York-based Human Rights Watch said "the ruling ZANU-PF party, the army and so-called war veterans have conducted a brutal state-sponsored campaign of violence, torture and intimidation against (opposition) activists and supporters.''

The group said limits on the opposition's access to the media and questions about the impartiality of electoral officials also have not been addressed.

"The ruling party's bloody crackdown on the opposition makes a free and fair run-off vote a tragic joke,'' Georgette Gagnon, Human Rights Watch's Africa director, said in the statement.

In a separate statement Friday, UNICEF said there were growing reports of children fleeing their homes with their families as a result of political violence and that aid groups were finding it increasingly difficult to operate.

Mugabe's officials have denied fomenting political violence, instead accusing the opposition of being behind the unrest.

Mugabe, 84, was hailed at independence in 1980 for promoting racial reconciliation and bringing education and health care to the black majority. But in recent years he has been accused of holding onto power through elections that independent observers say were marred by fraud, intimidation and rigging.