DR Congo police fired tear gas to prevent anti-government protesters gathering in the capital Kinshasa on Friday, forcibly escorting an opposition leader back home to stop him participating in the rally.
The attempted march was the latest protest by former presidential candidate Martin Fayulu since he lost a December 2018 election he claims was fixed in favour of President Felix Tshisekedi.
One person was slightly injured on the head by police, who turned out in force, firing tear gas to break up small groups of opposition supporters trying to rally, an AFP correspondent said.
The demonstration had been banned in advance by the authorities.
"They confiscated my money. I wasn't even there for the march," said Jean-Paul, who was bleeding from his head after saying he was roughed up by police on a main road in the city.
Security forces escorted Fayulu's car on foot and in vans back to his home, ensuring he could not march with his supporters following an early morning Roman Catholic Mass in the working-class Ndjili district.
Fayulu had called the demonstration to denounce militant attacks and what he calls the "Balkanisation" of the country's east, accusing officials of breaking up the region to the benefit of neighbouring countries like Rwanda.
"The DRC is already Balkanised. It just needs to be put into practice on the ground," said Blaise, a member of Fayulu's political party Ecide (Commitment to Citizenship and Development).
Militants have killed dozens of civilians around the town of Beni in North Kivu province in eastern DRC since the army began a crackdown on the group three months ago.
The massacres, blamed on the Allied Democratic Front (ADF), prompted local people to storm a base of the UN MONUSCO mission late in November, accusing peacekeepers of failing to protect them.
Fayulu challenged the result of the December 2018 election in the constitutional court, but his claim was rejected and Tshisekedi was declared the victor.
The European Union has said doubts remain over the results.
Officials banned Friday's march to "prevent breaches of the peace" on the public holiday marking the anniversary of the death of national independence hero Patrice Lumumba, who was assassinated on January 17, 1961.