Residents say several people wounded; Attack may have been response to Hezbollah leader Hassan Nasrallah's weekend speech in support of Assad.

Two rockets hit a Shi'ite Muslim district of southern Beirut on Sunday, residents said, wounding several people, a day after the leader of Lebanese Shi'ite militant movement Hezbollah said his group would continue fighting in Syria until victory.

One of the rockets landed in a car sales yard next to a busy road junction in the southern Chiah neighborhood and the other hit an apartment 300 meters away, wounding five people.

There was no immediate claim of responsibility and the army said it was investigating who was behind the attack.

A Lebanese security source said three rocket launchers were found, one of which had failed to launch, in the hills to the southeast of the Lebanese capital, about 5 miles (8 km) from the area where the two rockets landed.

The attack, close to Hezbollah's stronghold in southern Beirut, came just hours after its leader Hassan Nasrallah said his fighters were committed to Syria's war "to the end of the road."

Nasrallah said that Syria and Lebanon were facing a threat from radical Sunni Islamists, which he argued was a plot devised by the United States and its allies to serve Israel's interests in the region.

"We will not rely on anyone ... like all the battles before this one: We will be its people, its men, and we will be the ones who bring it victory," he said, speaking from an undisclosed location.

"We will continue to the end of the road, we accept this responsibility and will accept all sacrifices and expected consequences of this position," he said in the televised footage, which showed thousands of cheering people watching him on big screens in the Lebanese town of Mashgara.

Syrian President Bashar Assad comes from the minority Alawite sect, an offshoot of Shi'ite Islam. He has been bankrolled by regional Shi'ite power Iran and now increasingly by Hezbollah, Tehran's Lebanese proxy which was founded as a resistance movement to Israel.

Violence from the Syrian conflict, which began as a peaceful protest movement but descended into civil war, has increasingly spilled over into Lebanon, particularly in the northern city of Tripoli.

The bloodshed in Tripoli coincides with a fierce battle in Syria for the border town of Qusair, in which Hezbollah combatants have been fighting alongside Assad's army to drive out Syrian rebels who are supported by foreign fighters.

Nasrallah for the first time confirmed that his combatants were actively fighting in Syria, and said they had been there for several months. He said Hezbollah was not acting out of sectarian motives but to defend Lebanon from radical groups.

"Syria is no longer a place where there is a popular revolution against a political regime, rather it has become a place for imposing a political plan led by America and the West, and its tools in the region," he said in a speech to mark the 13th anniversary of Israel's withdrawal from southern Lebanon.