Zimbabwe's High Court has acquitted opposition leader Mr Morgan Tsvangirai on charges of plotting to overthrow and assassinate President Robert Mugabe.
"The evidence led has not shown beyond reasonable doubt that there was such a request [for an assassination and a coup d'etat]," Judge President Paddington Garwe said.
Mr Tsvangirai (52), the biggest challenger to President Robert Mugabe's 24-year-old rule, had pleaded not guilty to a treason charge of planning to kill Mr Mugabe and seize power ahead of presidential elections in 2002.
Security forces were on high alert after the government said it learned of plans to unleash violence when the court announces its verdict on Mr Tsvangirai.
Dozens of riot police stood on guard outside the court while more riot police set up roadblocks on some of Harare's main roads, searching vehicles heading towards the city centre.
Mr Tsvangirai still faces separate treason charges linked to anti-Mugabe protests his Movement for Democratic Change (MDC) organisation tried to organise in 2003.
Tensions have run high in the lead-up to the verdict, with the government and the MDC accusing each other's supporters of scheming to disrupt proceedings at the High Court.
The MDC had dismissed the trial as a charade intended to crush its five-year-old challenge to Mr Mugabe's grip on power, and has said that democracy was on trial in Zimbabwe.