KANO, Nigeria: Nigerian police and protesters clashed Monday and three people were shot dead as tens of thousands demonstrated nationwide over fuel price hikes and a general strike shut down the country.

The launch of what unions called an indefinite strike came at a crucial moment for Africa’s most populous nation and largest oil producer, already hit by spiraling violence blamed on Islamist sect Boko Haram.

Tensions particularly ran high in Kano, the largest city in Nigeria’s north, when thousands converged on the state governor’s office, prompting police to push them back as they fired tear gas and shot into the air.

Also in Kano, two vans were set ablaze and protesters tried to torch the home of central bank chief Lamido Sanusi, but police stopped them.

The office of the secretary of the state government – its highest administrative officer – was also set ablaze, causing serious damage.

A Red Cross official said that so far 30 injured had been counted in Kano, including 18 with gunshot wounds. A hospital source said later that two of those shot had died.

Nigerian officials announced a nighttime curfew for the northern city Monday night

In the southern city of Benin, protesters attacked a mosque and wounded several people, leading police to fire tear gas, police and witnesses said. A witness said he saw police take away a man with a machete cut on his head.

Protests appeared mainly peaceful in the economic capital Lagos, the largest city in Africa’s most populous nation, but a union leader accused police of shooting dead a demonstrator there.

Bonfires made of tyres burned along main roads in the megalopolis as protesters marched past, with an estimated 10,000 or more converging at a designated location for a rally.

Speakers denouncing the fuel price hike in Lagos included Femi Kuti, son of late musical icon and harsh government critic Fela Kuti, while prominent rights activists also took part.

Protest leaders in Lagos were keen to avoid provoking police after authorities were accused of using excessive force against demonstrators last week and shooting dead one person.

Some people threw stones after they believed police were seeking to turn them back. Police later pulled back and calm returned.

While the main group of protesters was largely peaceful, youths on the margins of the march set bonfires and threw bottles. Some yelled “Bad Luck Jonathan,” in reference to President Goodluck Jonathan.

“This is a peaceful demonstration,” said Ishola Adebayo, a 38-year-old teacher who took part in the Lagos march. “They cannot break our resolve to compel government to drop this anti-people policy.”

The strike was widely observed, particularly in Lagos, where the usually chaotic streets were empty apart from protesters, with shops, petrol stations and other businesses shut for the day.

Several thousand protesters also attended a rally in the capital Abuja despite massive security.

Officials said however that oil output was not affected in a country that produces around 2.4 million barrels per day.

The strike came after the government’s deeply controversial move to end fuel subsidies on Jan. 1, which caused petrol prices to more than double in a country where most of the 160 million population lives on less than $2 a day.

Transport costs have followed suit, sharply increasing the price of commuting, and further effects were feared, especially on the cost of food.

The strike comes as security forces are already under heavy pressure over spiraling violence blamed on Islamist group Boko Haram.

Recent deadly attacks on Christians have sparked fears of a wider religious conflict in a country whose population is roughly divided between a mainly Muslim north and predominantly Christian south.

On Dec. 31 Jonathan declared a state of emergency in hard-hit areas, but the violence, including gun and bomb attacks, has only continued and spread to other locations.

Much of the country has been united in anger against the abandoning of fuel subsidies despite a strong push from Jonathan and his respected economic team to make their case for the move. Nigerians view the subsidies as their only benefit from the nation’s oil wealth and lack any real trust in government after years of deeply rooted corruption.

The House of Representatives held an emergency session Sunday and approved a measure calling on the government to reinstate fuel subsidies to allow for further consultations on the issue. The government however made no sign it would back down.

Economists say removing fuel subsidies is vital for the country to improve its woefully inadequate infrastructure and ease pressure on its foreign reserves. The government says it spent more than $8 billion on subsidies in 2011.