Niamey (AFP) - Nigeria's Boko Haram fighters launched a new attack in neighbouring Niger on Monday, as parliament in Niamey was set to vote on joining a regional force against the Islamists.
The insurgents raided a prison in the southeastern border town of Diffa, which they first attacked on Friday, but were repelled after a heavy exchange of fire, humanitarian sources said.
"The attack failed. The assailants were quite easily pushed back," one source told AFP.
Following the rebuffed Boko Haram assault, witnesses in Diffa said a deadly explosion ripped through a local market just a day after it was struck by a mortar shell that killed one person and injured 20.
"Everything blew up -- I saw bodies everwhere," a local merchant told AFP by telephone Monday.
"There are deaths and injuries," concurred a local journalist, who says he counted one death and 15 people injured from the blast in Diffa's hospital.
The cause of the explosion still remains unknown, but suspicions focused on Boko Haram.
"We've known they have had sleeper cells here, that they were present for awhile. But now they've pressed the button to activate them," said a humanitarian worker.
The renewed violence -- the third attack in Niger in four days -- came as the country's parliament was expected on Monday to support a proposal to deploy troops inside Nigeria to help in the battle, along with soldiers from Chad, which has a battle-hardened army, and Cameroon.
No casualty toll was immediately available after the raid by Boko Haram, which has widened a deadly six-year insurgency in Nigeria with attacks in neighbouring countries.
A journalist in Diffa said he saw the bodies of alleged Boko Haram fighters being transported but was unable to count them.
Some Boko Haram fighters sought to hide out in the town. "The soldiers are looking for them, weapons at the ready. The army has encircled Diffa," the journalist said.
Another journalist said some of the fighters were being held in the prison they attacked.
- 'Chomping at the bit' -
Boko Haram leader Abubakar Shekau vowed in a new video released on Monday to defeat the military force taking shape to fight the militants in Nigeria, Cameroon and Niger.
The small nation of Benin, on Nigeria's western border, on Saturday agreed to join the alliance, which would include 8,700 troops, police and civilians.
But Shekau dismissed the force, previously set at around 7,500, saying: "We can seize them one by one."
Niger's Defence Minister Mahamadou Karidjo said Sunday that he hoped for a favourable parliamentary vote to "bring the final blow against the forces of evil".
"The boys are chomping at the bit to go" to fight Boko Haram, he said on public television.
"The defensive position our forces have held for more than three months is not a good position," Karidjo added. "We shall eradicate the Boko Haram plague in the region."
Niger said 109 jihadists were killed during an attack last week on Diffa and a simultaneous assault on Bosso, also close to the border, the first major assault in the country by Boko Haram.
Four soldiers and a civilian were also killed and another 17 troops were wounded.
Boko Haram also launched attacks in Niger on Sunday around Diffa, triggering running battles with local soldiers.
Niamey last December announced "the biggest military operation ever mounted in Niger" when it massed troops in the Diffa region.
According to the local governor, "nearly 3,000" soldiers are posted "every 10 or 15 kilometres (six or nine miles) along the border with Nigeria".
Chad deployed hundreds of tanks and other army vehicles on Nigerian territory more than a week ago, while other Chadian forces have moved into Cameroon to join the army there in the strategic town of Fotokol.