LAGOS (Reuters) - Hundreds of Nigerians marched through the streets of Lagos calling for a change of government on Monday, a rare show of public dissent that reflected mounting anger over an absentee president and a sputtering economy.

Flanked by a heavy police escort, more than 500 demonstrators halted traffic in the commercial capital as a truck blasted out protest songs against the administration of President Muhammadu Buhari.

Buhari has been in Britain since mid-January for unspecified medical checks and, with no indication of when he might return, many Nigerians suspect his health is worse than officials admit.

The country is also mired in its first recession in 25 years and high inflation is driving up prices of basic goods.

“Government of the rich, for the rich, making rules for the poor,” protesters chanted against a backbeat of anthems by Afrobeat superstar Fela Kuti, a fearless critic of Nigeria’s often brutal and corrupt military rule until his death in 1997.

“Unemployed people are hungry and angry,” read one demonstrator’s sign.

Buhari, whose age is officially given as 74, took office in 2015 on pledges to diversify the economy away from oil, fight corruption and end an Islamic insurgency by Boko Haram that broke out in the northeast in 2009.

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But critics say he has made little progress, with Nigeria still heavily dependent on exports of crude, the price of which has halved since 2014.

The still active insurgency has killed more than 15,000 people and led to a humanitarian crisis that has left 1.8 million Nigerians at risk of starvation and turned millions more into refugees.

Many of the more than 200 schoolgirls kidnapped by Boko Haram from the northeast town of Chibok in 2014 remain missing.

“We have a missing budget, missing Chibok girls and missing president,” the protesters chanted, also referring to the fact the 2017 budget has not yet been approved by parliament.

Vice President Yemi Osinbajo told an economic forum in Abuja that the government heard the protesters “loud and clear”.

“You have a right to demand for a better economy and we are committed to see it happen,” he said on Monday, but added: “Years of deterioration cannot be reversed overnight. ‎Again it has to be said that it’s our business, it’s our duty to ensure that we put the Nigerian economy on the track of recovery.”

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Some fear a rerun of the unstable three months when former President Umaru Yar’Adua was ill before he died, after which Vice President Goodluck Jonathan was sworn in in 2010.

Like Yar’Adua, Buhari is a Muslim from the north, and like Jonathan, the current president’s deputy Osinbajo is a southern Christian.

Traditionally the two religious groups have taken turns to hold the presidency, but that accord was unbalanced by the death of Yar’Adua before his first four-year term ended. Olusegun Obasanjo, his Christian predecessor, held office for the maximum eight years, while Jonathan was in power for five.

Nigeria is no stranger to ethnically- and religiously-charged violence. Conflict has swept the country’s heartland, where hundreds have died in clashes between Muslim herders and mainly Christian farmers, and militants continue to operate in the oil-rich Delta region in the southeast.