- The protesters are contesting the results of the presidential elections.
- President Nana Akufo-Addo won the vote with over 51 percent ahead of rival John Mahama.
- Five people were killed and 19 injured in election-related violence in Ghana.
Police in the Ghanaian capital Accra used water cannon on Thursday to disperse opposition supporters contesting the results of presidential elections.
Incumbent President Nana Akufo-Addo won the 7 December vote with 51.59 percent ahead of long-time rival John Mahama, with 47.36 percent, according to official figures.
Some 200 Mahama supporters wearing red and black marched to the headquarters of Ghana's Electoral Commission, carrying placards contesting the results.
They burned tyres in the middle of the road, causing a heavy traffic jam. Similar protests were held in other regions.
Ade Coker, regional chairman of Mahama's National Democratic Congress (NDC), said the protestors had come with a petition against the outcome of the polls.
"We have engaged in a peaceful march and everyone knows we're a peaceful party. Suddenly, we heard gunshots and teargas by the police resulting in total chaos," he said.
"We won't be intimidated. We're ready to protect our victory."
Police said they intervened to prevent a breakdown of law and order, and the water cannons were used to douse the fire.
Accra's head of police operations, Kwesi Ofori, said arrests had been made, but declined to give a number.
The elections' close outcome has fuelled tensions between the NDC and Akufo-Addo's New Patriotic Party (NPP), with Mahama accusing his rival of abuse of power.
Observers, both Ghanaian and foreign, viewed polling as generally free and fair, but police said five people were killed and 19 injured in election-related violence.
Ghana, a nation of 30 million people, has a reputation for electoral stability in politically volatile West Africa.