At least five suicide bombers attacked Lebanese soldiers as they raided two Syrian refugee camps in the Arsal area at the border with Syria on Friday and a sixth militant threw a hand grenade at a patrol, the army said.
The blasts killed a Syrian girl and wounded seven Lebanese soldiers as the army raided several refugee settlements, the military said.
The Lebanese army has been battling militants who are reportedly present in the border area with Syria during its war, now in its seventh year. Tiny Lebanon of 4.5 million people has been grappling with an influx of over a million Syrian refugees who escaped violence at home to find refuge in the neighbouring country.
Raiding refugee camps
The raids were part of a major security sweep by the army in an area that has been a flashpoint for violent spillover from the Syria crisis. According to an army statement, the soldiers were conducting early morning raids Friday in the town of Arsal when the attacks took place.
Several Daesh officials were among some 350 people detained, according to a security source.
But the raids also stirred up a storm among Syrian activists after pictures surfaced of rows of detainees with their faces to the ground, many bare-chested and their hands cuffed. The Britain-based Syrian Observatory for Human Rights called for their immediate release.
Some on social media alleged the photographs were of "terrorists" while others argued they were refugees mistreated by the Lebanese army.
Al Jadeed TV and other local media reported that about 400 people were detained during and after the raids, including some wanted militants believed to belong to an al-Qaida-linked group and the Daesh group.
Pictures circulated online showed dozens of men lying flat on the ground, with their hands cuffed behind their backs as soldiers stand above them with their guns pointed. The pictures could not be independently confirmed and the military could not be reached for comments on the detentions.
The town and the surrounding area was the scene of a major cross-border attack in 2014 when a number of Lebanese soldiers were abducted.
Series of blasts
The military said one suicide attacker blew himself up among a family of Syrian refugees during the raid in al Nour settlement, killing the girl.
Also in al Nour, three soldiers were wounded when a suicide bomber detonated his suicide belt near them. Three other men wearing suicide vests blew themselves up.
Attackers also detonated an explosive device while a military expert defused four others, the army said.
In another settlement, al Qariya, a fifth suicide bomber blew himself up but no one was hurt. But four soldiers were wounded when a hand grenade was tossed at them.
No group immediately claimed responsibility for the attacks.
Lebanon's army commander Brigadier General Joseph Aoun visited Arsal later Friday, praising his troops.
"What happened today reaffirms once again the army's decisive decision to eradicate terrorist organisations, their cells and members, wherever they are on Lebanese territory and regardless of the cost and sacrifices," Aoun was quoted as saying by the official Lebanese News Agency.
France, a major supplier for the Lebanese army, condemned the attacks.
Hosting over a million Syrians
Lebanon has faced limited spillover from Syria's civil war. The UN refugee agency says Lebanon hosts more than 1 million registered Syrian refugees - constituting a quarter of its population.
The government puts the number at 1.5 million. They are scattered across the country in informal tented settlements where many face the risk of arrest due to lack of legal residency that they struggle to obtain.
The Lebanese army has in recent months stepped up raids in the makeshift camps built on the edge of Arsal, where refugees live in squalid conditions.
The manhunt inside the sprawling camps on the border area came after intelligence reports that militants were preparing to stage a series of attacks inside Lebanon.
The country's defence minister was quoted as saying the incident showed the importance of tackling the refugee crisis and vindicated a policy of "pre-emptive strikes" against militant sleeper cells.
The camps around the town have long been considered a haven for militants coming from Syria who have clashed with Lebanese forces conducting security raids searching for suspects hiding among the refugees.
The militants briefly overran the town in 2014 in a battle that killed dozens and marked one of the more serious spillovers of the Syrian conflict in Lebanon.
Last summer, a series of deadly bombings struck a village near the Syrian border and killed five people. The attacks triggered fear among many in Lebanon.
But the images of the handcuffed detainees angered many Syrians, reeling from violence and abuse at home at the hands of the government and sometimes insurgents.
"We condemn the abuse and humiliation of Syrian refugees and we call on the Lebanese forces to stop such shameful acts," Rami Abdurrahman, the director of the Observatory said in a statement.