The jihadist group said it has taken the town of Gwoza in the north by force and that it intends to govern the whole of Nigeria under Islamic law.
Many soldiers believe their officers are siphoning off funds and leaking intelligence to Boko Haram.
Boko Haram has stepped up cross-border attacks into Cameroon in recent weeks, including a number of high-profile kidnappings.
Parents of girls kidnapped by Boko Haram describe their anguish, 100 days on.
Nobel prizewinner hits out at 'Boko Haramism' of Nigerian culture and the banalisation of graft.
Pakistan's Malala Yousafzai has held talks with some parents of the girls abducted in Nigeria and leaders of a group campaigning for their release.
The Nigerian military said it had killed 53 fighters from Boko Haram in northeasterly Borno state on Saturday.
Nigeria's military claims to have captured one of the group’s ringleaders – but the attacks continue unabated.
Beyond signing pledges to co-operate in fighting Islamic extremists like Boko Haram and al-Shabab, no real strategy is in place.
An attack on churches in northeast Nigeria blamed on Boko Haram killed more than 50 people ahead of Nigeria's last-16 World Cup match against France.
At least 10 people were killed in raids by suspected Boko Haram gunmen on two villages near Chibok where more than 200 girls were abducted in April.
Boko Haram's acts are a timely wake-up call for a nation that has slept through countless horrors, writes Ben Okri.
Twenty women have been kidnapped by suspected Boko Haram gunmen in northeast Nigeria, near Chibok.
Nigerian President Goodluck Jonathan is talking tough, but attacks could result in hostages being killed.
An extraordinary Ecowas security summit has announced plans for a partnership with Central African states to fight "terrorism" in the region.
Muslims and Christians in the volatile Nigerian city have closed ranks in the wake of deadly attacks intended to inflame religious tensions.
Discussions between Nigeria's military chiefs and the president over how to rescue schoolgirls abducted by Boko Haram have reached a stalemate.
While Nigeria's army says it knows where the girls kidnapped by Boko Haram are being held, they cannot use force to rescue them.
In what has become a deadly pattern of violence, gunmen have killed another 28 people in Nigeria.