The US has "aided and abetted" the Boko Haram Islamist militant group by refusing to provide weapons to Nigeria, its president says.
A US law prevents the government from selling arms to countries which fail to tackle human rights.
Nigeria's Muhammadu Buhari met President Barack Obama on Monday to seek further assistance.
Boko Haram has killed some 10,000 people since 2009 and has also kidnapped hundreds of girls and women.
Source: BBC