Movement for Democratic Change spokesperson Nelson Chamisa said Tsvangirai was taken to hospital but was not in a critical condition. He was still awaiting details.
Another party source said Tsvangirai’s wife Susan was killed.
Tsvangirai has formed a government with President Robert Mugabe, which offers a chance to ease the country’s economic crisis.
The new government faces an array of problems: food and fuel shortages, the world’s most serious hyperinflation and a cholera outbreak in which nearly 88 000 people have been infected, with nearly 4 000 killed, according to the World Health Organisation.
Zimbabweans and Western donors are hoping the new administration can deliver political stability after a power-sharing deal was reached in September after months of tough negotiations.
Tensions have been rising in the new government over the arrest of MDC official Roy Bennett.
Zimbabwean police have arrested a magistrate who tried to release Bennett while his case was still before the country’s highest court, a police spokesperson said on Friday.
Zimbabwe’s Supreme Court on Thursday granted prosecutors the right to appeal against a ruling by a High Court judge to grant bail to Bennett.
Livingstone Chipadze, a magistrate who refused to drop terrorism and banditry charges against Bennett two weeks ago, had tried to process the High Court’s bail ruling before the Supreme Court had heard the state’s appeal, police said.