Ivory Coast presidential candidate Guillaume Soro's planned return home was aborted on Monday as security forces waited at the airport and stormed his party headquarters in Abidjan.
Soro, a former rebel chief, landed in neighbouring Ghana after his private flight was diverted "against his will", his party said.
His scheduled return to the Ivory Coast as candidate in next year's ballot is raising tensions in the West African country whose 2010-2011 election ended in deadly violence between rival supporters.
Returning on a private flight following a six-month absence, Soro, 47, was diverted to Accra, according to Alain Lobognon, a spokesman for the Generations and People in Solidarity party or GPS.
In Abidjan, security forces in uniform and plain clothes stormed the GPS headquarters just after Lobognon told reporters Soro had been "prevented from returning to his country" to "take part in the electoral process."
A source close to the Ivory Coast presidency said Soro had asked the plane to land in Ghana to avoid "arrest upon arrival" in Abidjan.
Security personnel were present at the airport as well, according to an AFP reporter at the scene.
Around "800 men" including riot police were deployed along the route from the airport to Soro's home to "prevent any gathering" by supporters according to a note by Abidjan police officials that was sent to AFP.
The GPS headquarters, in a private home next to the US embassy in Abidjan, had been surrounded by armed men who pushed their way inside and forced the occupants to leave.
Police also fired tear gas, and members of the media and party loyalists were driven from the area.
Soro is a former ally of President Alassane Ouattara, but the two since have had a falling out, reportedly owing to Soro's own presidential ambitions.
Political analysts say Soro is popular in particular among young Ivorians, but there are no independent opinion polls to estimate his support nationwide.
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Violence in 2010-2011 that followed a previous election caused 3,000 deaths, and local elections last year were also marred by fraud and fighting.
Soro, a Christian from the north of the country, headed rebels fighting against then president Laurent Gbagbo in the country's civil war in 2002.
The revolt cut the former French colony into a rebel-held north and government-controlled south, triggering years of unrest.
Gbagbo was later ousted after refusing to concede defeat to his arch-rival Ouattara in the 2010 election.
Soro's support was crucial to Ouattara, whom he then served as prime minister in 2011-2012.
Soro had already held that position from 2007-2012, and was also president of the national parliament from 2012-2019.