Abuja (AFP) - Nigeria insisted it will crush Boko Haram militants and avoid another election postponement, even as violence raged and the Islamists' leader vowed to defeat a regional force hunting them.
National Security Advisor Sambo Dasuki's comments came as Boko Haram launched another attack in neighbouring Niger and reports emerged of 20 people kidnapped in Cameroon, with 12 of them executed.
Niger's parliament voted unanimously on Monday to send troops to join the regional fightback against the extremists, who have seized swathes of northern Nigeria in a conflict that has claimed more than 13,000 lives since 2009.
Dasuki, who at the weekend secured a six-week delay to Nigeria's presidential elections, vowed that "all known Boko Haram camps will be taken out" by the time of the rescheduled vote.
"They won't be there. They will be dismantled," he told AFP in an interview when asked what gains could be made against the Islamists before the new polling date of March 28.
Nigeria has previously set deadlines to defeat the insurgents that have come and gone.
But Dasuki said that even if the goal was not achieved "the situation then would surely be conducive enough for elections", with no need for a further postponement to voting.
Meanwhile Boko Haram chief Abubakar Shekau mocked west African leaders' multinational force in a new video on YouTube on Monday, saying it "won't achieve anything."
The Islamists last week opened up a new front in Niger after sustained attacks in Cameroon's far northern region, which led to the deployment of Chadian troops alongside Cameroon forces.
They have widened their offensive in recent weeks in the far north-east of Nigeria around Lake Chad, where the borders of all four countries converge.
Niger, while housing thousands of refugees from the conflict, had been mainly spared the violence until last week. Monday's unanimous parliamentary vote to send troops to join the fightback will see some 750 soldiers deployed, a lawmaker said.
Just hours before the vote, militant fighters raided a prison in Diffa, southeast Niger, but were repelled.
A deadly explosion then ripped through a local market, with one local merchant saying: "Everything blew up -- I saw bodies everywhere."
On Sunday, suspected Islamists kidnapped 20 passengers aboard a bus going from Koza to Mora in the far north of Cameroon, then killed 12 of them and released the rest.
"Every day citizens are frequently kidnapped in this region," a security source said. "Some are usually freed when their families negotiate, while others are killed."
- Militants mock regional fightback -
Boko Haram released three new videos on YouTube, one of them a 28-minute speech from its leader Shekau in an undisclosed location flanked by eight masked fighters.
He dismissed the threat from regional forces, stating: "Your alliance will not achieve anything."
Nigeria maintains that the involvement of troops from Chad and Cameroon is part of an existing agreement to fight the Islamists between countries in the Lake Chad region.
On Saturday, Nigeria and its neighbours -- Chad, Niger, Cameroon and Benin -- agreed to muster 8,700 troops, police and civilians for a wider, African Union-backed force against Boko Haram.
The United States estimates Shekau as having between 4,000 to 6,000 hardcore fighters at his disposal, and he mocked regional efforts to defeat them.
"You send 7,000 troops? Why don't you send seven million?" he said in Arabic.
"By Allah, it is small. We can seize them one by one."
Shekau also directly threatened Chad's President Idriss Deby, whose forces have attacked Boko Haram in the northeast Nigerian towns of Gamboru and Malam Fatori in recent days.
- 'We rose up to fight the world' -
Shekau's speech appeared to put the Boko Haram insurgency in the wider context of global jihad, possibly in response to the regional nature of the conflict.
In the last six years, the group has mainly operated in three states in northeast Nigeria, taking over a succession of towns and villages as part of its aim to create a hardline Islamic state.
Boko Haram has been considered to have essentially local aims and is thought to have few direct, operational links to jihadi groups elsewhere, although it is believed to include some foreign fighters, most likely paid mercenaries.
But Shekau has mentioned groups such as Al-Qaeda in the Islamic Maghreb (AQIM) and the leader of the so-called Islamic State group in Syria and Iraq, Abu Bakr al-Baghdadi.
One of the three latest videos shows Baghdadi with archive footage and a voiceover recalling a battle between British soldiers and fighters from the Sokoto Caliphate in northern Nigeria.
The Sokoto Caliphate was dismantled by British colonialists who annexed the northern Islamic kingdoms and the predominantly Christian south to form Nigeria in the early 20th century.
In his speech Shekau appears to broaden the group's aim: "We never rose up to fight Africa. We rose up to fight the world.
"We are going to fight the world on the principle that whoever doesn't obey Allah and the Prophet to either obey or die or become a slave."