HARARE, Zimbabwe (CNN) -- Zimbabwe's President Robert Mugabe spoke at a memorial service Tuesday for the wife of Prime Minister Morgan Tsvangirai, who was killed last week in a car wreck.
Morgan Tsvangirai addresses mourners Monday at his house in Harare soon after his return from Botswana.
"We are doing our best that we create a conducive environment and tell our supporters that the issue of violence must end," he said.
Hundreds of people gathered at the Glamis Stadium in the capital, Harare, for Tuesday's memorial service for Susan Tsvangirai. The funeral will take place Wednesday in Tsvangirai's rural village of Buhera, south of the capital.
Marriam Garwe said she traveled 200 kilometers (124 miles) to attend Tuesday's service.
"I want to pay my last respects to Mrs. Tsvangirai," said Garwe, 43, who is from Mutoko. "I am sad that she died before Mr. Tsvangirai is the president."
Morgan Tsvangirai, a leading opposition figure, recently joined a power-sharing government with Mugabe after last year's bloody election campaign.
Members of Tsvangirai's political party, the Movement for Democratic Change, initially said the prime minister believed Friday's crash that killed his wife was an assassination attempt.
Tsvangirai, who was hurt in the wreck, dismissed those assertions Monday.
"When something like that happens there is speculation, but I want to assure you, if it was foul play it is one in a thousand," he said after returning home from neighboring Botswana. "It was an accident that took her life."
Don't Miss
Tsvangirai rules out foul play in fatal crash
Magistrate arrested in Zimbabwe; activists freed
Attorney: Release of Mugabe opponent unlikely
Mugabe has made an effort to show his sympathy and support for Tsvangirai, his political rival. He visited the prime minister in the hospital and has said the government will provide a state-assisted funeral for Susan Tsvangirai.
Tsvangirai has long been a leading opposition figure in Zimbabwe, but he joined a coalition government with Mugabe last month. That seemed to resolve an impasse created by a disputed presidential election between Mugabe and Tsvangirai last year.
Tsvangirai received the most votes in the March 2008 election, but he fell short of the 50 percent required to avoid a runoff. He withdrew as a candidate in the runoff, citing political violence and intimidation targeting his supporters.
Negotiations between the two sides culminated in the power-sharing agreement that was implemented just weeks ago.
Questions about the wreck surfaced shortly after it happened Friday on a busy two-lane highway between Tsvangirai's hometown of Buhera and Harare.
The secretary-general of Tsvangirai's party, Tendai Biti, said police should have provided better security for Tsvangirai. The wreck might not have happened, he said, if a police escort been on hand.
A former U.S. ambassador to Zimbabwe, Tom McDonald, said the wreck raised suspicion.
"I'm skeptical about any motor vehicle accident in Zimbabwe involving an opposition figure," said McDonald, who was ambassador to Zimbabwe from 1997 to 2001.
"President Mugabe has a history of strange car accidents when someone, lo and behold, dies -- it's sort of his M.O. of how they get rid of people they don't like."
McDonald, however, was quick to add that traffic accidents are common in Zimbabwe. The highway on which Tsvangirai was traveling is a two-lane road on which tractor-trailers are common, he said. Vehicles in the country are often in bad shape and many drivers are inexperienced, he said.
"It's certainly plausible that this was just one of those tragic things," he said.