Nigeria's National Security Adviser has said the country's general election, which has been postponed until March 28, will not be moved again and that all known camps belonging to the armed group Boko Haram will be destroyed in the next six weeks.

"All known Boko Haram camps will be taken out. They won't be there. They will be dismantled," Sambo Dasuki told reporters on Monday.

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"Those dates will not be shifted again," Dasuki said when asked if the polls, initially scheduled for February 14, could be pushed back further.

Dasuki said he believed the new military co-operation agreed to between Nigeria and its neighbours - Cameroon, Chad and Niger - will prove decisive against Boko Haram.

Dasuki had urged election officials on Saturday to postpone the vote on the grounds that the military could not provide nationwide election security because all available resources were being deployed to the northeast to fight Boko Haram.

His justification for the delay was widely criticised, in part because the military is not primarily responsible for election security in Nigeria.

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Troops have only been called in when police and civil defence units have needed reinforcements.

Dasuki said there was no political motive underlying his call for a delay.

He added that the postponement could easily help the opposition All Progressives Congress (APC), because improved security could boost turnout in the northeast, an APC stronghold.

The APC leader, former General Muhammadu Buhari, speaking exclusively to Al Jazeera on Sunday, said the elections should not have been postponed but that his party would ask their supporters to remain calm.

"There is no need for it [the delay]," he said.

"If the same military can not secure 14 local governorates out of 774 in six years, how can they be sure they can secure those 14 in six weeks?"

Boko Haram threat

As regional forces ramp up their fight against Boko Haram, the group's leader Abubakar Shekau released a video on Monday vowing to defeat the planned 8,700-strong African military deployment.

Shekau said: "We can seize them one by one."

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Neighbouring Niger's parliament voted unanimously on Monday to send troops to Nigeria.

The vote came just hours after a fresh attack in Niger blamed on Boko Haram.

Fighters launched an assault on a prison in the southeast, the third assault on the border town of Diffa since Friday, but were repelled after a heavy exchange of fire, humanitarian sources said.

Authorities ordered locals to stay in their homes and mounted roadblocks around the town by late morning. Residents and humanitarian officials said thousands of people were fleeing from the town in cars and motorbikes.

In Cameroon, a security source told the AFP news agency that suspected Boko Haram fighters attacked the northern village of Kerawa on Sunday and kidnapped at least 18 people travelling on a bus near Adanga Danga.