At least eight people have been killed in the Lebanese border town of Arsal as the country's army claimed it targeted Syrian rebels.
Security sources and residents in Arsal told Al Jazeera that Monday's attack hit a rebel gathering, but it was not immediately clear whether the victims were civilians or rebels.
At least 10 others were wounded.
The AFP news agency cited a separate security source, saying a "helicopter fired a missile at takfiri [extremist Sunni] positions in Wadi Hmeid" on the eastern outskirts of Arsal.
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The Lebanese army has battled rebels along the border with Syria for over a year in sometimes bloody clashes.
The border area is also home to informal Syrian refugee camps largely beyond the reach of authorities or aid agencies.
Lebanon's National News Agency said an "explosion in the Syrian refugee camps killed four people and injured others", but gave no further details.
Security sources denied the camps were hit.
Arsal is in the country's northeast and over half of its population are Syrian refugees. A largely Sunni town, it was the site of fierce fighting in August 2014 between Lebanese security forces and rebels from al-Qaeda's Syria affiliate and the Islamic State of Iraq and the Levant (ISIL) group.
As they withdrew from Arsal, the fighters took dozens of Lebanese security forces hostage and still hold many of them in the hilly terrain on the town's outskirts.
Source: Al Jazeera and agencies