Cameroon opposition leader Maurice Kamto, who claims to have been cheated out of the presidency in elections last year, was arrested in the country's economic capital Douala on Monday, a senior party member said.
"Mr Kamto was arrested at the home of (supporter) Albert Dzongang," said Emmanuel Simh, vice-president of the opposition Movement for the Rebirth of Cameroon (MRC), confirming information from a source in Douala.
Dzongang and Christian Penda Ekoka, an economist, were also arrested in the police raid, Simh told AFP.
The authorities, when contacted, did not respond to an AFP request for information on Monday's events.
Following Kamto's arrest, around 300 people gathered outside Dzongang's house.
Shots were fired into the air to disperse the crowd.
Kamto has continued to claim he was the rightful winner of last October's presidential election.
Veteran leader Paul Biya, in power for 36 years, won a seventh consecutive term in the election blasted by the MRC as an "electoral hold-up".
Kamto won 14.23% of the vote to place second, according to the official figures, but his party has held sporadic protests since then to dispute the result.
On Saturday 117 people were arrested during protest marches in several towns.
Kamto's former election campaign head Paul-Eric Kingue and rapper Valsero were among those detained over the weekend.
Biya has ruled the West African country since 1982 with support from the army, government administrations and the Cameroon People's Democratic Movement (CPDM) that he created in 1985.