HARARE, Zimbabwe — President Mugabe said today he is open to talks with the opposition, which is boycotting tomorrow’s runoff because its leader says state-sponsored violence has made it impossible to take part.

World leaders have dismissed the runoff as a sham and Nigeria became the latest African nation to call for its postponement, but electoral officials say the election will go ahead with the opposition leader, Morgan Tsvangirai, on the ballot. Mr. Tsvangirai predicted that people could be forced to go to polling stations.

“There could be a massive turnout not because of the will of the people, but because of the role of the military and the role of traditionally people being forced to the polls,” Mr. Tsvangirai said today in an interview with British Broadcasting Corp.

Mr. Mugabe had shown little interest in talks and his government had scoffed at the Movement for Democratic Change’s call yesterday to work together to form a transitional authority.

“We remain open to discussion with the MDC,” Mr. Mugabe said while speaking at a campaign rally at Chitungwiza, about 15 miles south of the capital.

But the Zimbabwean deputy information minister, Bright Matonga, said Mr. Mugabe’s words did not indicate that the leader was softening toward the opposition. He said Mr. Mugabe had always insisted that the runoff must take place in accordance with the country’s constitution.

Mr. Matonga would not say how soon after the election the two parties would meet, saying that if Mr. Mugabe won the election he would address the nation soon afterward.

Prior to Mr. Mugabe’s comments, Mr. Tsvangirai was quoted today as saying negotiations won’t be possible if Mr. Mugabe goes ahead with runoff.

“Negotiations will be over if Mr. Mugabe declares himself the winner and considers himself the president. How can we negotiate?” Mr. Tsvangirai said in an interview with the British newspaper The Times.

Mr. Tsvangirai won the first round of the presidential election on March 29, but did not gain an outright majority against 84-year-old Mr. Mugabe, who has held power since independence from Britain in 1980.

The March campaign was generally peaceful, but the runoff has been overshadowed by violence and intimidation, especially in rural areas. Independent human rights groups say 85 people have died and tens of thousands have been displaced from their homes, most of them opposition supporters.

Mr. Tsvangirai, the only candidate facing Mugabe in tomorrow’s runoff, announced Sunday he was withdrawing and then fled to the Dutch Embassy for safety.

In the capital, Harare, more than 300 opposition supporters have fled to the South African Embassy, fearing for their lives.

The Red Cross at Zimbabwe has supplied food, blankets, and tents to the group sheltering in the embassy, the South African ambassador to Zimbabwe, Mlungisi Makalima, said in a statement.

The Foreign Ministry of Nigeria, Africa’s most populous nation, said the vote should be postponed because it was “doubtful” that a credible election could be held.

Yesterday the leaders of Swaziland and Tanzania, meeting as a committee of the main regional bloc, the South African Development Community, also urged a postponement.

Also today, Zimbabwe opposition party’s No. 2 official, who has been charged with treason, was granted bail and released from jail.

Tendai Biti was required to surrender his passport and the title to his home and report to police twice a week in addition to bail set at 1 trillion Zimbabwean dollars, or about $100, a lawyer, Lewis Uriri, said.

Mr. Biti returned to his home in the capital late afternoon, two weeks after he was jailed looking tired and frail but still sounding defiant.

“Some people stay 27 years in prison so two weeks is nothing,” he said in an interview with Associated Press Television News. “It wasn’t easy though but we have to continue fighting.”

Anti-apartheid icon Nelson Mandela, who criticized Zimbabwe’s leadership yesterday, spent 27 years in a jail before becoming South Africa’s first democratically elected president.

Today, both the government and the opposition reacted strongly to Mr. Mandela’s criticism, with Mr. Mugabe’s spokesman dismissing the comments and Mr. Tsvangirai reverently welcoming them.

The information minister, Sikhanyiso Ndlovu, said Mr. Mandela was only bowing to Western pressure when he spoke of Zimbabwe’s “tragic failure of leadership” at a London fundraiser. Keenly aware of Mr. Mandela’s status as anti-apartheid icon, Mr. Ndlovu condemned the West for pressuring African leaders, not Mr. Mandela.

Mr. Mandela rarely differs publicly with the South African president, Thabo Mbeki, but many Africans have questioned Mr. Mbeki’s unwillingness to criticize Mr. Mugabe, his neighbor.

“We appreciate the solidarity from Nelson Mandela,” Mr. Tsvangirai said. “It is something we cherish.”

Meanwhile, Mr. Mugabe continued to campaign like an actual presidential race was taking place. The Herald reported today he had urged crowds north of Harare to “vote for the ruling party to show the world their resolve to defend the country’s sovereignty and independence.”

Mr. Mugabe has become increasing defiant in the face of international condemnation over his mismanagement of the southern African nation’s economy.

Mr. Mugabe was lauded early in his rule for campaigning for racial reconciliation. But in recent years, he has been accused of ruining the economy and holding onto power through fraud and intimidation.

The official inflation rate was put at 165,000% by the government in February, but independent estimates put the real figure closer to 4 million%.

Since the first round of national elections, shortages of basic goods have worsened, public services have come to virtual standstill, power and water outages have continued daily, and streets and highways have crumbled.

The economic slide of what was once the region’s breadbasket has been blamed on the collapse of the key agriculture sector after often-violent seizures of farmland from whites. Mr. Mugabe claimed he ordered the seizures, begun in 2002, to benefit poor blacks. But many of the farms instead went to his loyalists.