Fuel prices remain a contentious issue in Nigeria
Six Nigerian trade union activists have been arrested for demonstrating at petrol stations which failed to comply with a deal on fuel prices last week.
They have been charged with criminal conspiracy and inciting public disturbance for allegedly picketing at the petrol stations.
A leader of the Nigeria Labour Congress (NLC) - the senior assistant general secretary, Linus Ukamba - was among those detained by police in the capital, Abuja.
Last week, the NLC called off a strike to protest against an increase in fuel prices after private petrol station owners agreed to a reduction in fuel prices.
But there has been confusion with some petrol stations continuing to sell fuel at the higher rate.
Members of the NLC sang defiant songs outside the court in Abuja, as the magistrate hearing the case remanded the six in custody until Monday when their bail application will be heard.
The president of the NLC, Adams Oshiomhole, told the BBC outside the court that the arrests and detention of the six labour activists were unjust.
"This is an additional incentive to remind us that Nigeria is far from being a country of justice," he said.
He added the NLC would continue to picket petrol stations until a solution acceptable to all sides was found.
"Unless and until they jail the last man, the picketing will continue," Mr Oshiomhole said.
After last week's strike was called off, President Olusegun Obasanjo launched a stinging attack on leaders of the NLC in a nationwide address on Wednesday night, accusing them of attempting to form a parallel government.
"The leadership of the NLC has engaged in a series of subversive activities, deliberately misrepresenting government policies to the public and to its members and using every opportunity to blackmail the government and others who hold contrary opinions or views," he said.
The threat of nationwide industrial action had led to large queues at petrol stations, banks and shops as people tried to stock up with essential supplies on Wednesday.
Nigeria is Africa's largest oil exporter, but refines little of its own crude oil and relies on expensive imports of petrol, diesel and heating oil.