Opposition forces in Syria on Sunday accused the Lebanese group Hezbollah of “military intervention” that threatened “regional peace and security.”

According to a statement released by the Syria National Council (SNC) and quoted by AFP, Hezbollah militants on Saturday attacked three villages in Homs province, near the Lebanese border, causing “civilian casualties and the exodus of hundreds of people.”

“In the past two days, 12 Syrian rebels were killed and 30 wounded, while three Hezbollah members were killed and 14 others were wounded in battles,” a Lebanese security source told The Daily Star.

The involvement of the militant group “stoked sectarian tensions” in the area, the SNC statement said.

Hezbollah is considered a close ally of embattled President Bashar Assad, whose presence at the helm of the Syrian regime has provided the Shiite faction with an invaluable link to Iran.

The SNC is the main opposition bloc leading a two-year revolt against Assad that has claimed the lives of some 70,000 people.

Hezbollah involvement is a “serious threat to Syrian-Lebanese relations and regional peace and security,” the SNC said, laying blame for the “aggression” at the doorstep of the Lebanese government.

But a Hezbollah source quoted by The Daily Star said that the rebels were to blame for the outbreak of fighting. Shells fired by Syrian opposition forces had landed in the Lebanese town of Qasr, but did not cause any casualties, the source reportedly said.

“The Hezbollah force moved on foot and was supported by multiple rocket launchers. The Free Syrian Army had to call in two tanks that had been captured from the Assad army to repel the attack,” Hadi al-Abdallah of the Syrian Revolution General Commission told Reuters.

Israel and the West have expressed deep concern that with Assad apparently losing his grip on power, Hezbollah could come into possession of part of Syria’s sizable stockpile of chemical weapons, or acquire “game-changing” weapons that are in the hands of the Assad regime.

Last week, The Washington Post reported that Iran, which supplies Hezbollah with much of its weaponry, was setting up a network of militias in Syria that would enable the Islamic Republic to maintain its influence in the region even if the Syrian government topples.

In late January, Israeli jets reportedly attacked a truck convoy headed from Syria into Lebanon that Western and Israeli officials said was carrying Russian-made anti-aircraft missiles intended for Hezbollah. Syria claimed that the target was a military research facility.

Hezbollah condemned Israel, calling the alleged strike a “barbaric” attempt to stunt “Arab and Islamic technological development.”