BEIRUT - The leader of Lebanon's Hezbollah militant group vowed to help propel President Bashar Assad to victory in Syria's bloody civil war, warning that the fall of the Damascus regime would give rise to extremists and plunge the Middle East into a "dark period."
In a televised address, Sheikh Hassan Nasrallah also said Hezbollah members are fighting in Syria against Islamic radicals who pose a danger to Lebanon. He pledged that his group will not allow Syrian militants to control areas along the Lebanese border. And he vowed that Hezbollah would turn the tide of the conflict in Assad's favor and stay as long as necessary to do so.
"We will continue this road until the end. We will take the responsibility, and we will make all the sacrifices," he said. "We will be victorious."
The Hezbollah leader's comments offered the clearest public confirmation yet that the Iranian-backed group is directly involved in Syria's war. They also were Nasrallah's first remarks since Hezbollah fighters pushed to the front lines of the battle for the strategic Syrian town of Qusair near the Lebanese frontier.
The fighting in Qusair, which government troops backed by Hezbollah pounded with artillery on Saturday, has laid bare the Lebanese Shiite group's growing role in the Syrian conflict. Hezbollah initially tried to play down its involvement but could no longer do so after dozens of its fighters were killed in the town and buried in large funerals in Lebanon.
Nasrallah, who was speaking on the anniversary of Israel's withdrawal from southern Lebanon in May 2000, used his speech in part to brace the community for the possibility of more of its men returning home in coffins.
The fight in Qusair has proven a deadly grind for both sides. On Saturday, government forces backed by Hezbollah militants shelled the town in the heaviest barrage yet of a weeklong assault to dislodge rebels from the opposition stronghold, activists said.
Since the regime offensive began Wednesday, Syrian state media has said government forces have steadily gained ground. Local activists deny that pro-Assad forces have made headway and say rebel fighters are defending their positions.
The Syrian government has been one of Hezbollah's strongest backers for decades, and the militant group fears that if the regime falls it will be replaced by a U.S.-backed government that will be hostile to Hezbollah.
Nasrallah on Saturday defended his group's deepening involvement and sought to frame the fight next door as part of a broader battle against Israel.
"Syria is the back of the resistance, and the resistance cannot stand, arms folded while its back is broken," Nasrallah told thousands of supporters from a secret location via a video link.
"If Syria falls into the hand of America, Israel and takfiris, the resistance (Hezbollah) will be besieged and Israel will enter Lebanon and impose its will," Nasrallah said. Takfiri Islamists profess an ideology that urges Sunni Muslims to kill anyone they consider an infidel.
Syria's fall, he said, would mean "Palestine will be lost" and "the people of our region and its nations will enter a bad and dark period."