Nigeria's President Muhammadu Buhari on Thursday declared a "national emergency on corruption", as he signed a new executive order to freeze suspected ill-gotten gains.He also revealed public funds allegedly stolen by those on trial or under investigation topped $1.6bn - enough to finance much-needed government projects.Signing the order to restrict dealings in suspicious assets, Buhari restated his view that "if Nigeria does not kill corruption, corruption will sooner or later kill Nigeria".The new order to curb illicit activities, including selling off the proceeds of crime, was an effective way of tackling graft and its harmful effects, he said."Accordingly, the Federal Government of Nigeria has declared a national emergency to deal with that crisis," he added.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTER FOLLOW News24 Africa on Twitter and FacebookNigeria may have made billions of dollars from its oil and gas industry over decades but most of its more than 180 million people live in poverty.Buhari attributed the yawning wealth gap to endemic corruption and indicated the money involved in current prosecutions could have helped improve education, jobs and roads."From available records, the aggregate value of funds involved in some on-going prosecutions of high-profile corruption-related cases stands at 595 409 838 452 naira," he said.That eclipsed the 500 billion naira in this year's budget for school-feeding programme and job-creation schemes. Some 344 billion naira was allocated for seven major road projects.Buhari, who is seeking a second, four-year term of office at elections in February next year, came to power on a pledge to tackle endemic corruption in Africa's most populous nation.He has vowed to recover what he said were "mind-boggling" sums stolen from the public purse by corruption officials of previous administrations, as well as push greater transparency.Measures include the introduction of a single account for the remittance of government revenue, anti-fraud measures at high-street banks and a crackdown on tax evaders.But critics have accused of him of mounting a political witch-hunt, as most of those under investigation or brought before the courts are his party political opponents.The glacial pace of the Nigerian justice system has also left the government without a big-name scalp in the much-vaunted anti-corruption drive.