The army general said that the gunmen attacked army positions near the town of Arsal and troops returned fire. Another official said the gunmen also took control of the main police station in the town, but did not elaborate further.

The general said gunmen took a number soldiers and police officers from their homes in Arsal, as well as two soldiers who were driving an army tanker truck. It was not clear if they were taken across the border into Syria or if they were still in Arsal.

The general said the government sent reinforcements to the area. The general and the official spoke on condition of anonymity as they weren't authorized to speak publicly.

Arsal is home to tens of thousands of Syrian refugees and rebels enjoy wide support among its population. Syria's civil war has spilled over into Lebanon on several occasions, leaving scores dead.

The violence on the border with Lebanon came after an ambush near the border killed dozens of opposition fighters, activists said. The Britain-based Syrian Observatory for Human rights said Syrian troops and members of Lebanon's Hezbollah group ambushed opposition fighters in the Qalamoun region near the Lebanese border, killing at least 50 of them. It said seven troops and Hezbollah fighters were killed in the fighting.

Syrian state television reported clashes in Qalamoun that killed "tens of terrorists." Syrian media refers to all opposition fighters as terrorists.

Government troops backed by Hezbollah fighters have seized nearly all the strategic Qalamoun region since launching an offensive there last November, severing rebel supply lines from neighboring Lebanon.

The Syrian uprising began in the form of peaceful protests against President Bashar Assad in March 2011, but escalated into an uprising when government forces violently cracked down on dissent.

The country is now in the grip of a complex civil war pitting several rebel and Al-Qaeda-linked groups against the government and each other. Over 170,000 people have been killed in Syria in more than three years of fighting, activists say.

The last two weeks of July were among the deadliest yet in the conflict, with at least 2,000 people killed. Nearly half the deaths were reportedly government soldiers or affiliated militias.

United Nations Secretary General Ban Ki-moon said in late June that the humanitarian situation in Syria is becoming worse, with the number of people needing urgent help reaching 10.8 million — nearly half the population. Over 9 million Syrians have been forced to flee their homes.

Ban said the use of barrel bombs by government forces had intensified in civilian areas, and on the other side extremist groups such as ISIS were increasing suicide attacks and reportedly brutal executions.

Wire services