Thousands of demonstrators have marched through Nigeria's main city of Lagos in protest at a 30% rise in fuel costs after subsidies were cut last month.
It is the beginning of two weeks of peaceful protests to take place across Nigeria organised by trade unions.
At one point, the noisy and colourful gathering stretched for more than 3km through the city's streets.
Police have been ordered not to carry firearms in the first sanctioned anti-government protest in 40 years.
Nigeria is Africa's largest oil exporter, but is dependent on imports of fuel because it does not have enough refining capacity to meet its own needs.
"Stop fuel importations, make our refineries work," some placards read.
Strike not ruled out
The Catholic Archbishop of Lagos, Cardinal Olubunmi Okogie, and Nobel Prize winner Wole Soyinka joined the 13km march.
The unions say price hikes affect badly all Nigerian workers
Two-thirds of Nigeria's population is still living on less than $1 a day, and the unions say the fuel price increases will badly affect all Nigerian workers.
Last month, President Olusegun Obasanjo said that the government had financed more than $1bn in fuel subsidies in the past six month as a result of high prices of refined petrol on the international markets.
"Petrol is God's gift to Nigeria. Why can't Obasanjo allow us to enjoy it?" asked a 24-year-old demonstrator.
After two week, the Nigerian Labour Congress (NLC) will meet to decide if further action is needed, depending on the government's reactions.
The BBC's Sola Odunfa in Lagos says a general strike in October has not been ruled out.
Last year, the NLC called three crippling general strikes against fuel prices rises.
Under legislation passed in March, umbrella unions, such as the NLC, are not allowed to call a strike.