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, and pledged that his group will not allow Syrian militants to control areas along the Lebanese border. He pledged that Hezbollah will 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 have 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 week-long 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 Britain-based Syrian Observatory for Human Rights said at least 30 people, including 27 rebels, were killed and dozens wounded Saturday in the town, which holds strategic importance for both the regime and the opposition.
For Assad, Qusair's value lies in its location along a land corridor linking two of his strongholds, the capital of Damascus and towns on the Mediterranean coast, the heartland of his minority Alawite sect, an offshoot of Shiite Islam. For the rebels, holding Qusair means protecting a supply line to Lebanon, 10 kilometers (six miles) away.
Saturday's barrage of rockets, mortar rounds and tank shells began after daybreak, said Qusair activist Hadi Abdullah and the pro-opposition Observatory. Both said it was the most intense shelling since the regime launched its offensive there a week ago.
Hezbollah has come under harsh criticism at home and abroad for sending its gunmen to Qusair, and Nasrallah's gamble in Syria primarily stems from his group's vested interest in the Assad regime's survival. 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 refers to 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."
Along with Iran, Syria has been the main backer of Hezbollah. Much of the group's arsenal, including tens of thousands of rockets, is believed to have come from Iran via Syria or from Syria itself.
Hezbollah's role has drawn intense criticism from Syria's main opposition group.
"Some Lebanese are being sent to Syria as invaders in order to return back home in coffins draped with shame," said George Sabra, the acting head of the Syrian National Coalition.
More than 70,000 people have been killed and several million displaced since the uprising against Assad erupted in March 2011 and morphed into a civil war. The Syrian government and Hezbollah deny there is an uprising in Syria, portraying the war as a foreign-backed conspiracy driven by Israel, the U.S. and its Gulf allies.
The Syrian conflict poses a threat to the stability of Lebanon, whose sectarian divide mirrors that of Syria, and the fighting next door has repeatedly spilled over the border. For the past week, Assad's opponents and supporters have been clashing in the Lebanese port city of Tripoli, using mortars, grenades and machine guns to attack densely populated areas.
Sniper fire in Tripoli killed four people on Saturday, bringing the week's death toll to 29 including three Lebanese soldiers, according to a Lebanese official who spoke on condition of anonymity in line with military regulations. More than 200 people have been wounded.
Nasrallah said Lebanon should be spared the fighting over Syria's crisis and called upon rivals to go fight in Syria.
"You are fighting in Syria and we are fighting in Syria. Let's fight there. Let's keep Lebanon away from the fighting," Nasrallah said referring to Lebanese Sunni militants who are fighting alongside the Syrian opposition.
Hezbollah is also facing repercussions in Europe over its support for the Syrian military.
Earlier this week, France and Germany joined a push by Britain to have the EU declare Hezbollah's military wing a terrorist organization. Such a move, long sought by the U.S., would hamper Hezbollah operations in Europe.
Nasrallah said the threats by the EU "is all ink on paper" adding that this will not affect the group.
"We have been under pressure for 30 years and it did not affect our morale," he said.
Meanwhile, Syria's fractured political opposition failed Saturday after three days of intense deliberations to reach a decision on whether to attend an international conference brokered by the U.S. and Russia aimed at ending the conflict in Syria.
The U.S. and Russia want to bring together representatives of the opposition and the Syrian government at an international conference in Geneva for talks on a possible transition government. Much remains up in the air, including the date, the agenda and the list of participants.
The Syrian National Coalition meetings started Thursday and were scheduled to end Saturday but discord among the fractured opposition delayed the discussions. The talks now were expected to continue Sunday, opposition figures said.
On Friday, Syria ally Russia said the Assad regime has accepted in principle to attend talks in Geneva, though there has been no official statement from Damascus.
The opposition is deeply suspicious about Assad's intention to hold serious peace talks, and senior opposition figures have ruled out attendance unless Assad's departure tops the agenda of such negotiations.