The Lebanese army has recaptured a third of an enclave held by so-called Islamic State near the north-eastern border with Syria, officials say.
Troops launched an offensive near the town of Ras Baalbek on Saturday.
The army says there are about 600 militants in the mountainous area, which IS has held since 2014 and is the group's last stronghold in the country.
About 20 militants have been killed in the latest operation and 10 soldiers have been injured, the military says.
The offensive was aimed at ridding the area of IS militants, who are armed with anti-aircraft and armour-piercing missiles and drones, the Lebanese army said.
Youssef Roufeyel, a resident of Ras Baalbek, told Reuters news agency that local people would do whatever was necessary for victory.
"This battle requires help and support from the people, and we are behind the army and by their side," he said.