BEIRUT >> Rockets slammed into two Beirut neighborhoods that are strongholds of Lebanon’s Hezbollah group, wounding at least 4 people, Lebanese security officials and media said.

Tensions have been running high in Lebanon, and Syrian rebels have threatened to retaliate against the militant Shiite Hezbollah group for sending fighters to assist President Bashar Assad’s forces in Syria.

One rocket landed in the Mar Mikhael district on the southern edge of the capital, striking a car exhibit on the street today. Another struck an apartment in a building in Chiyah district south of Beirut, about two kilometers (one mile) away from Mar Mikhael.

Hezbollah’s Al-Manar TV said the Chiyah rocket did not explode.

The officials spoke on condition of anonymity in line with regulations and said it was not clear from where the rockets were fired.

The state-run National News Agency said among the wounded were three Syrians.

On Saturday, Hezbollah leader Sheikh Hassan Nasrallah vowed to help propel 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, he 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.