Lawmakers in Abuja were also set to debate a request from President Goodluck Jonathan for a six-month extension to a state of emergency first imposed in three northeast states worst affected by insurgent violence exactly a year ago.
Boko Haram, which has waged an increasingly deadly campaign of bombings and attacks in the last five years, kidnapped 276 girls from the remote town of Chibok in Borno state on April 14.
Street protests, including in a torrential downpour in Nigeria’s financial capital, Lagos, marked the one-month anniversary of the girls’ abduction, calling for the 223 still being held to be returned to their families.
The United Nations expressed its “deep concern” about the fate of the teenagers.
The head of the Committee on the Elimination of Discrimination Against Women, Nicole Ameline, said the mass abduction violated UN conventions and “may qualify as a crime against humanity”.
“The Committee urges Nigeria to employ all necessary means to obtain the release of the girls and to bring to justice the perpetrators of this heinous crime,” she said in a statement.