NEW : At least four people are killed and 77 injured in a large blast in Beirut , state media say . - A suicide bomber kills at least three police officers outside the U.S. Embassy in Beirut. The neighborhood hit by the car bomb is known as a Hezbollah stronghold . Tensions are rising in Lebanon ; many are angered by Hezbollah 's role in Syria 's conflict .
NEW : At least four people are killed and 77 injured in a large blast in Beirut , state media say . U.N. representative in Lebanon condemns `` yet another appalling act of terrorism '' The neighborhood hit by the car bomb is known as a Hezbollah stronghold . Tensions are rising in Lebanon ; many are angered by Hezbollah 's role in Syria 's conflict .