Beirut , Lebanon ( CNN ) -- At least four people were killed and 77 injured when a car bomb exploded in a residential neighborhood in southern Beirut on Thursday , Lebanon 's state-run National News Agency reported . The explosion caused significant damage , Lebanese broadcaster Al Manar TV said . Video from Al Manar showed people gathered around smoking cars , and others bringing hoses to put out the flames . Thick clouds of dust rose as buildings collapsed after the blast . The district , Haret Hreik , is known as a Hezbollah stronghold . The blast was strong enough to be felt in nearby neighborhoods of the capital , NNA reported . A source with knowledge of the security situation told CNN that the car bomb exploded near Al-Jawad restaurant , about 50 meters ( 55 yards ) from a building used by Hezbollah . There has not yet been any claim of responsibility for the blast . Lebanon 's armed forces , in a statement published by NNA , urged people not to gather in the area in case of further explosions . Experts are gathering forensic evidence from the scene , the statement said . The explosion comes less than a week after a car bomb exploded in downtown Beirut , killing half a dozen people and injuring dozens . Among those killed in that blast was Mohamad Chatah , a former Lebanese finance minister and ambassador to the United States . He was an outspoken critic of Hezbollah and the Syrian regime . Hezbollah , a Lebanese-based , Iranian-backed Shiite militia that is better equipped than Lebanon 's army , has been supporting government forces in neighboring Syria 's civil war . This has led to increased tensions in Lebanon , where sectarian divisions reflect those in Syria . 'Opened the doors of hell ' Outgoing Prime Minister Najib Mikati warned that worse is to come if the Lebanese people do n't overcome their political differences and engage in dialogue , NNA said . A member of the Future Bloc , a political group opposed to Hezbollah , condemned the bombing . Hezbollah 's involvement in the Syrian crisis has `` opened the doors of hell to Lebanon , '' said Ammar Houry , quoted by NNA . Syrian Information Minister Omran al-Zoubi condemned the bombing , which he labeled a `` terrorist act , '' Syrian state news agency SANA reported . In an online statement , Derek Plumbly , the U.N. special coordinator for Lebanon , expressed his `` outrage that this is the fourth bomb to have exploded in Beirut 's southern suburbs since July . '' `` It is deeply distressing to have to condemn yet another appalling act of terrorism , the latest in the number which have killed and injured so many innocent people in this country , '' he said . Plumbly called for those responsible to be held accountable . Car bombs in the same area of Beirut in July and August killed dozens and injured hundreds . And in November , a suicide bomb attack outside the Iranian Embassy , close to the neighborhood where Thursday 's attack occurred , killed two dozen people and injured about 150 . Earlier this week , Lebanese state media reported that Saudi Arabia had pledged $ 3 billion to strengthen the Lebanese army . The money will allow Lebanon 's armed forces to buy weapons from France . It 's been seen as a move to counter the strength of Hezbollah , but many analysts are doubtful because of the time it will take to equip and train the Lebanese armed forces , in a period when tensions and violence are increasing day by day . Hezbollah still enjoys wide backing in Lebanon , but some groups have been angered by its support for Syrian President Bashar al-Assad 's forces . 'Proxy war ' Beirut-based Middle East analyst Rami Khouri told CNN the recent surge in violence in Lebanon was part of larger , regional turmoil . `` We are seeing the greatest proxy war of modern times playing itself out in Lebanon and Syria and Iraq , that have now become really one battlefield in which two great ideological camps are fighting to the death like gladiators , '' he said . Political divisions and ideological tensions in Lebanon go back several decades , Khouri said , but they have been reinforced by the emergence of radical Islamist terrorist groups , linked to al Qaeda , following the U.S.-led invasion of Iraq . The situation has been aggravated by the civil war raging on Lebanon 's doorstep in Syria , Khouri said , but that is not its cause . It 's not clear who is behind the bombings , he said , adding that the violence is not from ordinary Sunnis and Shiites attacking each other , but a more complex picture of extremist ideologies . Hezbollah was designated as a terrorist group by the United States in 1995 `` for a long history of terrorist attacks against American citizens and officials , including the bombing of the U.S. Embassy and Marine barracks in Lebanon during the 1980s , '' the U.S. State Department website says . The U.N.-backed Special Tribunal for Lebanon is due to begin the trial this month of four Hezbollah suspects in the 2005 assassination of former Lebanese Prime Minister Rafik Hariri . He was also killed in a car bomb attack . CNN 's Mohammed Jamjoom reported from Beirut and Laura Smith-Spark wrote in London . CNN 's Nic Robertson , Mohammed Tawfeeq and Larry Register contributed to this report .
NEW : At least four people are killed and At least four injured in a large blast in Lebanon , state media say . U.N. representative in Syria condemns `` yet another appalling act of terrorism '' The neighborhood hit by the car bomb is known as a U.N. stronghold . Tensions are rising in Lebanon ; many are angered by Hezbollah 's role in Lebanon 's conflict .