Nigerian President Muhammadu Buhari has ordered the arrest of the former national security adviser, accusing him of stealing about $2 billion through phantom arms contracts and hampering the fight against Boko Haram militants, his office said.
The arrest order is part of a campaign by Buhari, who was elected in March, to tackle corruption, which has enriched an elite but left most Nigerians in poverty.
Buhari's office said former security adviser Sambo Dasuki had "awarded fictitious and phantom contracts" worth around $2 billion for jets, helicopters and ammunition, which were never delivered, for the army to fight the Boko Haram group.
Dasuki had also instructed the central bank to transfer more than $140 million to accounts in Britain, the United States and West Africa "without any contract documents," the statement from the presidency said.
Under Buhari's predecessor Goodluck Jonathan, when Dasuki was in office, Boko Haram, an armed group that took control of parts of Nigeria's northeast, where it is trying to carve out a state that adheres to its interpretation of Islamic law.
"Had the funds siphoned ... been properly used for the purpose they were meant for, thousands of needless Nigerian deaths would have been avoided," the presidency said late on Tuesday.
Dasuki, who lives in the capital Abuja, rejected the claims, saying there had been no fictitious contracts and no money diverted. "I did not use the office for any self-serving agenda," he said in a statement.
Arms procurement was supposed to be under the purview of the Defense Ministry, but Jonathan to shift the task to the National Security Adviser in September last year. Normally the NSA only advises on procurement.
Military sources complained they were given little notice or say in what they needed and had to be creative with whatever equipment arrived.
Nigeria has had to seek arms from a wide range of eastern European and Asian countries, as some Western states, which previously provided equipment, were concerned with human rights abuses.
Large orders finally arrived early this year and were key in turning around the fight against Boko Haram, according to diplomats.
This year, Nigeria, backed by its neighbors, was able to recapture much of the territory lost to Boko Haram though suicide bombings and other attacks blamed by officials on the militant group remain part of daily life in the north.
Boko Haram has waged a six-year campaign which has killed thousands of people and displaced 2.1 million.