At least one person was killed in the unrest in Lagos, and a large mob of people pushed the body in a wheelbarrow down the street. And in the northern city of Kano, another two died and at least 31 people were wounded when security officers used tear gas and fired at crowds protesting the fuel price hikes.
Protesters in Lagos took gasoline from motorbikes to set tires ablaze. And some demonstrators waved placards bearing an effigy of President Goodluck Jonathan with devil horns and fanged teeth, and showing him pumping fuel at a gas station.
"Our leaders are not concerned about Nigerians. They are concerned about themselves," said protester Joseph Adekolu, a 42-year-old accountant.
Police carrying Kalashnikov rifles and gas masks in Lagos largely stood by as the demonstrators marched on the first day of an indefinite strike called by labour unions. Protesters also took to the streets in Nigeria's capital of Abuja.
However, at least one person died following an altercation in the Ogba neighbourhood, according to a witness who spoke on condition of anonymity fearing police reprisals. The police officer accused of shooting him has been arrested, said Lagos state police spokesman Samuel Jinadu.
In Nigeria's second-largest city of Kano, protest organizer Ashiru Sharif said two young men were shot dead by security officers who opened fire on a crowd of chanting protesters.
"We were not attacking anybody," said Sharif, adding that 24 other peaceful protesters were wounded.
Meanwhile, angry protesters broke down part of the fence at the seat of Kano's state government where security officers also shot at people, wounding about seven others.
Gas prices have risen from $1.70 per gallon (45 cents per litre) to at least $3.50 per gallon (94 cents per litre) since a government fuel subsidy ended on Jan. 1 at the orders of Jonathan's administration. That spurred a spike in prices for food and transportation across a nation of more than 160 million people, most of whom live on less than $2 a day.
While lawmakers on Sunday rebuked the president's decision, the unions said they would continue their strike.
Bola Adejobi, 53, said she's protesting against more than just fuel costs. For her and many others in Africa's most populous country, the strike represents anger that much of the nation remains without electricity and clean drinking water after more than 50 years of oil production.
"It is high time to take Nigeria into our hands," Adejobi said. "It happened in Egypt. It happened in Libya."
Nigeria's finance minister said the country has been using borrowed funds to maintain the subsidy.
"Greece got where it is now because, for years, they didn't do the right thing. They kept borrowing and borrowing to finance development," Ngozi Okonjo-Iweala told local television station Channels TV on Monday. "We can't keep borrowing to finance our development."
Two major unions have said they will maintain the strike despite a court restraining order. A similar situation occurred in 2003, when strikers over eight days attacked shops that remained open, took over air traffic control towers and caused a drop in oil production in a country vital to U.S. energy supplies.
The strike comes as activists have begun a loose-knit group of protests called "Occupy Nigeria," inspired by those near Wall Street in New York. Their anger extends to the government's weak response to ongoing violence in Nigeria by a radical Muslim sect that, according to an Associated Press count, killed at least 510 people last year.
Famous Nigerian authors, including Chinua Achebe, issued a statement Monday saying they support the strike, and warning that if left unattended the violence by the extremist group could sweep the country.
"The country's leadership should not view the incessant attacks as mere temporary misfortune with which the citizenry must learn to live; they are precursors to events that could destabilize the entire country," their statement read.
The government has so far failed to calm public anger over the spiraling gasoline costs. The government has promised that the $8 billion in estimated savings a year from the end of the fuel subsidies would go toward badly needed road and public projects.
One protester in Lagos held his protest sign upside down.
"Our life is already turned upside down," he told a reporter. "It is not how it's supposed to be."
Associated Press writers Ibrahim Garba in Kano, Lekan Oyekanmi in Abuja and Yinka Ibukun in Lagos, Nigeria contributed to this report.
Jon Gambrell can be reached at www.twitter.com/jongambrellAP.