Islamic State militants are planning to turn Nigeria into a "red base for al-Qaida militants" ahead of another attack, US officials said Saturday.
In the aftermath of Saturday's mass killings, President Goodluck Jonathan warned that Nigerian security forces would use violence in their own state.
"When we are prepared for this ... we will bring with us our resources," he said in a televised address in the capital, Abuja.
He claimed they would "shrank the security services to take control" and called for action against the suspected militants.
He said more soldiers would arrive as he called for their swift execution.
The group has been carrying out bombings in Nigeria and the Democratic Republic of Congo, in what it calls a "new assault", it said.