Lebanon's army has detained more than 100 Syrians for entering the country illegally following a series of suicide bombings in a border village.
The raids took place at informal refugee camps in the Baalbek region.
On Monday, at least eight bombers blew themselves up in the predominantly Christian village of Qaa, killing five people and injuring almost 30 others.
No group has said it was behind the attacks, but suspicion has fallen on jihadist militants from Islamic State.
IS has carried out previous suicide bombings that have killed scores of people in Lebanon.
Lebanon's official National News Agency (NNA) cited an army statement as saying that troops had raided Syrian refugee encampments on Tuesday and arrested 103 Syrians "for not having legal papers". Nine motorbikes were also confiscated.
Troops also searched the Qaa Projects (Masharia Qaa) camp for "wanted individuals", according to an NNA reporter in the area.
Masharia Qaa is located outside the village of Qaa, where the mayor advised residents to stay indoors after Monday's unprecedented attacks.
In the first wave of attacks, four suicide bombers blew themselves up one after the other at dawn outside a house in Qaa.
Five people were killed and another 15 wounded, including four soldiers who went to investigate the first blast.
It was not immediately clear who or what the attackers planned to target, but the house was about 150m (490ft) from a Lebanese customs border point on the road linking the Bekaa valley to the Syrian town of Qusair.
Emotions running high - Carine Torbey, BBC News, Qaa
In the main square of Qaa, a statue of Saint Elias, holding his sword menacingly, stands tall and imposing.
Emotions are running high in the predominantly Christian border town, where anger is mounting towards tens of thousands of Syrian refugees living in makeshift settlements nearby.
The mayor described the residents of these encampments as "ticking bombs".
As such, the suicide attacks might have been a turning point in the relationship between the Lebanese and the Syrian refugees there; from annoyance to suspicion and accusation.
The consequences for both groups could be dire.
Many residents believe that ultimately the saint will protect the town. But they are not only counting on God's intervention. People openly carry weapons, from guns to rifles, dangling from their waists or in their grasp.
They are vowing to take security in their own hands.
Soon after nightfall on Monday, 13 other people were wounded when another four assailants opened fire and detonated their explosive vests near the Church of Saint Elias, shouting "Allahu Akbar" ("God is greatest"), NNA said.
People had reportedly gathered at the church for the funerals of those killed that morning.
The army later issued statements calling on residents not to gather anywhere in the area and requesting that the funerals be postponed until further notice.
Baalbek-Hermel governor Bashir Khodr also imposed a curfew on Syrian refugees living in the village and surrounding areas.
"The security situation today is above all considerations," Mr Khodr told the television channel LBC.
The militant Shia Islamist movement, Hezbollah, blamed the attacks on IS and said it was postponing a religious event in Beirut on Tuesday.
Foreign Minister Gebran Bassil, who visited Qaa after Monday morning's attacks, said the border villages formed part of a "fence" for Lebanon. "When a terrorist enters, he can go anywhere," he added.
Mr Bassil, whose Free Patriotic Movement party leads the largest Christian bloc in parliament, called on Sunday for municipalities to ban gatherings or camps of Syrian refugees.
Lebanon has seen repeated attacks linked to the five-year conflict in Syria, where Hezbollah has sent thousands of fighters to support President Bashar al-Assad.