BEIRUT — Two rockets crashed into southern Beirut suburbs controlled by the militant group Hezbollah on Sunday, wounding four people in what appeared to be the first attack on the group’s stronghold in more than two years of sectarian tensions here over the civil war next door in Syria.
It was unclear who fired the rockets, which Lebanese authorities said came from the hills southeast of the city. Syrian rebel leaders denied involvement.
But some rebel commanders threatened last week to hit the area in retaliation for Hezbollah’s growing role in the fierce battle for the strategic Syrian town of Qusair.
Hezbollah’s leader, Hassan Nasrallah, declared Saturday that his forces would fight to the end to support their allies in the Syrian government of Bashar Assad.
The attack raised fears of increased spillover violence in Lebanon, where many Sunni Muslims support the mainly Sunni Syrian rebels and sectarian clashes have worsened in the northern city of Tripoli. It made plain that not everyone had heeded Nasrallah’s call Saturday for supporters and opponents of the Syrian government to spare Lebanon by taking their fight to Syria.
In a separate development Sunday, the Assad government confirmed that it has agreed in principle to attend UN-sponsored talks with opposition representatives in Geneva next month on ending the war,the Associated Press reported.
Foreign Minister Walid al-Moallem of Syria said during a visit to Iraq that such talks present a ‘‘good opportunity for a political solution for the crisis in Syria.’’
He did not say under what terms Assad would dispatch representatives.
The date, agenda, and list of participants for the conference remain unclear. Syrian opposition leaders have said that they are willing to attend the Geneva talks but that Assad’s departure from power must top the agenda.
Assad said this month that his future won’t be determined by international talks and that he will only step down after elections are held.
Hezbollah, Lebanon’s most powerful political party and Shi’ite militia, and its main political rivals all say they have a stake in easing the violence in Lebanon, which bears the scars of its own 15-year sectarian civil war. The prospect of all-out conflict here still seems remote to most.
But after the rocket strikes Sunday, anxieties seemed to run higher than at any point over the past few years, and a parade of Lebanese officials called for calm.
Reflecting Lebanon’s deep divide over Syria, some mainly condemned Sunday’s attack while others blamed Hezbollah’s plunge deeper into Syria.
“Lebanese citizens and leaders should be awakened by this warning before Lebanon explodes,” the country’s mufti, Sheik Mohammad Rashid Qabbani, a Sunni, told Lebanon’s LBC television.
Near the impact site in Hezbollah’s stronghold — known simply as the Dahiya, the Arabic word for suburb — residents on Sunday said the attacks would not deter the group’s followers.