An ally of Zimbabwean President Robert Mugabe has said the result of next month's run-off election will be respected.
The state-run Herald newspaper reported that Emmerson Mnangagwa, a government minister and Mr Mugabe's chief election agent, said that the president 'will be the first one to go on national television to acknowledge the result to the people'.
Mr Tsvangirai beat President Mugabe in the 29 March presidential poll but failed to win an absolute majority.
His Movement for Democratic Change, which has accused Mr Mugabe's government of cheating in past elections, fears it will rig the results of the 27 June run-off.
But Mr Mnangagwa added that President Mugabe and his ruling ZANU-PF party were confident they would win the second round of voting.
The 84-year-old Zimbabwean ruler kicked off his re-election campaign yesterday, accusing the US of political interference in Zimbabwe's affairs and the MDC of training youths to engage in political violence.
He threatened to kick out US ambassador James McGee and said the US State Department's top Africa envoy had behaved like a prostitute for suggesting that Mr Tsvangirai had won the 29 March poll. The MDC won control of parliament in a parallel election.
Robert Mugabe, who has ruled Zimbabwe since independence from Britain in 1980, routinely accuses the US and Britain of backing the MDC to punish him for seizing thousands of white-owned farms since 2000.
He also says Western sabotage is to blame for Zimbabwe's economic meltdown. The southern African nation is struggling with inflation of more than 165,000%, unemployment of 80% and chronic food and fuel shortages.
Some 3.5m people have fled to South Africa and other countries to escape poverty and malnutrition.
Grassroots campaign
Mr Mugabe and his ZANU-PF party have signalled they intend to pursue a grassroots campaign focused on voter canvassing and small village meetings ahead of the run-off, eschewing the mass rallies they have favoured since 1980.
The MDC draws much of its backing from the capital Harare and other cities. Mr Mugabe, whose popularity has plunged as the economy has collapsed, needs to be able to offset that if he is going to win.
The Zimbabwean ruler is still admired by many of his own citizens and others in Africa for leading the battle to end British colonial rule, and a grassroots campaign may tap into that legacy.
Morgan Tsvangirai also launched his campaign after returning to Zimbabwe on Saturday for the first time since early April, repeating his demand that the government ends the political violence that has engulfed the nation since the March polls.
The MDC says dozens of its supporters have been killed or beaten in an intimidation campaign orchestrated by ZANU-PF. The ruling party says the MDC is responsible for the bloodshed.
