Nigerian police have fired tear gas and bullets to disperse protesters on the second day of a general strike against rising fuel prices. At least 80 people were arrested Monday.

There was more unrest Tuesday as police pushed workers past picket lines gathered outside government offices in Abuja. Militants also set fire to barricades in the streets in Lagos.

The strike has affected mainly Abuja and Lagos, shutting down most transport in those two cities. Oil industry officials say the key oil sector in the southeast has not been affected, even though world oil prices have moved higher over fears Nigerian exports would be disrupted.

Nigeria is Africa's biggest oil exporter, but it also faces massive fuel shortages, because most of the oil is shipped abroad. The hike in fuel prices follows a decision by the government to slash its massive subsidies to domestic consumers.

President Olusegun Obasanjo explained at the start of the strike, that the savings would be used for the good of all Nigerians.

He says, "Why should we use the money that we should use to service our education, our health, our roads, our agriculture to supply fuel?"

The price hike is also part of government efforts to deregulate the oil sector, to make it more competitive and efficient.

Union leaders say authorities should first end mismanagement corruption and oil smuggling. They also say ordinary Nigerians should not bear the cost of reform.

Authorities have warned the strike action is illegal, but union leaders say it is the only way to start a dialogue.