Voters line up in Harare to cast their ballots in Friday's presidential election. (Associated Press)

Election marshals led voters to polling stations and bands of government supporters harassed people in the streets Friday as Zimbabwe held an internationally discredited, one-candidate presidential run-off election.

Opposition leader Morgan Tsvangirai, who withdrew from the run-off against longtime President Robert Mugabe citing a campaign of state-sponsored violence, said it was "not an election. It is an exercise in mass intimidation."

He spoke to journalists during a brief outing from the Dutch Embassy in Harare, where he took refuge earlier this week.

President Robert Mugabe reacts after casting his vote in Harare on Friday while his wife, Grace, looks on. (Tsvangirayi Mukwazhi/Associated Press)

Tsvangirai’s Movement for Democratic Change (MDC) won parliamentary elections in late March, and claimed a clear victory over Mugabe in the presidential portion of that vote.

But Mugabe’s ZANU-PF party said the result was too close to call and Friday’s run-off election was called to determine a clear winner.

Tsvangirai told journalists that Mugabe’s government was forcing people to vote.

Paramilitary police in riot gear deployed in a central Harare park Friday, then began patrolling the city. Militant Mugabe supporters roamed the streets, singing revolutionary songs, heckling people and asking why they were not voting.

Bands of young men in ruling party T-shirts demanded to see peoples’ fingers to check for the indelible ink mark that is put on at polling stations.

"I've got no option but to go and vote so that I can be safe," a young woman selling tomatoes told the Associated Press.

A Movement for Democratic Change spokesman in Britain told CBC News that the run-off had been "a joke."

"It confirms that we are not only dealing with a ruthless dictator, but one who is not in full control of his senses," Hebson Makuvese said in an interview from London, England.

Situation 'not normal': observer

Independent election observers said Zimbabweans were forced to the polls and were too frightened to talk.

"Some of them are saying, 'We were told to come here,"' Pan African Parliament spokesman Khalid A. Dahab said. "It's just not normal. There's a lot of tension."

Rindai Chipfunde-Vava of the Zimbabwe Electoral Support Network said she was hearing persistent reports of forced voting, people's names and ballot serial numbers being written at polling stations and illiterate people assisted to vote by government supporters.

"This run-off is marred by a low turnout and a heavy police presence," Chipfunde-Vava told CBC News. "The pre-election violence and the withdrawal of Morgan Tsvangirai [will] affect the legitimacy and the credibility of this result."

World leaders roundly condemned the vote. Secretary of State Condoleezza Rice, speaking at a meeting in Japan, called the vote a "sham," and said the United States would use its position as president of the UN Security Council until July 1 to lead international condemnation of Mugabe's regime.

"Those operating in Zimbabwe should know that there are those ... who believe that the Security Council should consider sanctions," Rice said. "We intend to bring up the issue of Zimbabwe in the council. We will see what the council decides to do."

In another development, the 15-member council unanimously "agreed that the conditions for free and fair elections did not exist and it was a matter of deep regret that elections went ahead in these circumstances," U.S. Ambassador Zalmay Khalilzad said on behalf of the council, after three hours of private talks among its members.

Prime Minister Stephen Harper said Canada believed Mugabe had stolen the vote, and this country would be part of international efforts to push for democratic change in Zimbabwe. Harper called the election an "ugly perversion of democracy."

African countries ponder response

A meeting of African foreign ministers in Egypt is considering what steps the continent's nations can take to press for change in Zimbabwe.

"I don't think we are going to accept the result but we are still discussing," a minister told Reuters, asking not to be identified.

African leaders will meet at the Red Sea resort of Sharm-el-Sheikh Sunday, with Zimbabwe at the top of the summit agenda. Mugabe is expected to attend and observers say his presence will be a real test of the African Union's ability to deal with a political crisis in its own backyard.

The presidents of Burundi, Kenya, Rwanda, Tanzania and Uganda, in a rare comment about the affairs of another African country, said Zimbabwe's one-candidate runoff, "cannot be a solution," to the country's political crisis.

The presidents, at a regular summit of the East African Community held in Kigali, Rwanda, urged Mugabe's and Tsvangirai's parties "to come together and work out an amicable solution through dialogue in the interest of all Zimbabweans."

Jacob Zuma, the head of South Africa's African National Congress, said the situation in Zimbabwe was "extremely difficult and distressing."

"We reiterate that the situation is now out of control," he said in one of the few openly critical comments about the Zimbabwean situation a senior South African politician has made.

"Nothing short of a negotiated political arrangement will get Zimbabwe out of the conflict it has been plunged into."

Economy in freefall

On Thursday, Mugabe said he was "open to discussion" with the opposition but only after the vote. Mugabe had shown little interest in talks and his government had scoffed at Tsvangirai's call Wednesday to work together to form a transitional authority.

The MDC leader has said his offer to hold talks with Mugabe would lapse if the run-off election went ahead.

Mugabe's government is generally blamed for the dire economic situation in Zimbabwe.

Inflation is running at more than 100,000 per cent a month, unemployment is at 80 per cent and there are chronic shortages of food and fuel.

With files from the Associated Press