Maurice Kamto, the main rival of Cameroon President Paul Biya, walked free from prison on Saturday after insurrection charges against him were dropped in what the government said was a gesture of national reconciliation.
After a hearing at a military tribunal, Kamto, wearing a dark suit and blue tie, was released to a crowd of cheering supporters in the capital Yaounde.
Biya, who has governed Cameroon for nearly four decades, is seeking to calm unrest stoked by a disputed presidential election last year and a separatist insurrection that has cost close to 2,000 lives over the past two years.
Kamto, the head of the opposition Cameroon Renaissance Movement (MRC), finished runner-up to Biya in last October's presidential election but denounced the result as fraudulent.
He was arrested in January after leading protests which security forces dispersed with live bullets, and faced charges before a military court which his lawyers said could have carried the death penalty.
The government announced on Friday that some MRC members would be freed, saying Biya was determined "to relentlessly pursue his efforts to find ways to peacefully resolve the disagreements confronting our country".
Besides Kamto, about 100 other CRM members were released, lawyers involved in the case said.
"This release is a good thing. It shows good faith," Felix Agbor, one of Kamto's lawyers, told Reuters. "But I think it's necessary to pardon others who have already been convicted."
Biya also ordered 333 other prisoners arrested in the conflict with Anglophone separatists freed on Thursday as part of week-long talks aimed at ending the rebellion.
The insurrection, which began as peaceful protests by English speakers against their perceived marginalisation by the French-speaking majority, now aims to create an independent state including Cameroon's two Anglophone regions.
It has emerged as the biggest security challenge of Biya's tenure, forcing half a million people from their homes.
But separatist leaders have rejected Biya's recent overtures to bring an end to the conflict and dismissed Thursday's announcement as a political stunt.