A little known Syrian rebel group has claimed responsibility for a car bomb attack that hit the southern suburbs of Beirut on Tuesday, wounding 53 people.
It also claimed it was behind an attack on a Hezbollah convoy in eastern Lebanon on June 28.
The group, named the Special Forces 313 Brigade, uses the black, red, green and white colours of the flag of the Syrian opposition, and Islamic terminology.
It describes itself as "an independent military formation, that fights in Syria for the victory of God's word."
"Special units from the 313 Brigade staged an attack using a car bomb in the Bir al-Abed area of the southern suburbs," the group said on its Facebook page.
"We warned again and again against (Hezbollah's) intervention in Syria," the brigade added.
It cited "the failure of Lebanese politicians to control" the party as one of the reasons for the attack.
Hezbollah publicly intervened in the conflict in neighboring Syria in April, siding with President Bashar al-Assad's forces against the rebels in the strategic battle to gain control of Qusayr.
The Bir al-Abed car bomb attack, which wounded 53 people, was the most serious incident in Beirut's suburbs since the start of the Syria war more than two years ago.
"This attack was not the first and it will not be the last, and (Hezbollah) knows full well who targeted its soldiers in the Ksara area of Zahle (in eastern Lebanon) last month," said the 313 Brigade's statement.
On June 28, two small explosive devices went off in Zahle targeting a Hezbollah convoy.
In May, two rockets launched from hills above the capital struck Beirut's southern Chiyah district, injuring four Syrian workers.
"We will chase down any remnants of this terrorist group, wherever they may be, until they stop taking part in the bloodletting of the Syrian people," the 313 Brigade warned.
Mainstream rebel group the Free Syrian Army condemned the attack in the densely-populated Dahiyeh neighborhood, describing it as a "terrorist" act.
"The position of the FSA supreme command is clear – we condemn this as a terrorist attack that targeted civilians, and do not consider it a military operation," its political and media coordinator, Louay Muqdad, said.