BEIRUT, Lebanon — The second deadly car bomb to strike the Beirut area in less than a week exploded on Thursday in a southern suburb of residential apartment buildings that is home to top Hezbollah offices and heavily populated with the group’s supporters.

The blast created a black column of smoke visible across the city, shattered windows 11 floors up and hurled debris hundreds of feet. It accelerated the tempo of political violence, which is mostly fueled by deep splits between Lebanon’s Sunnis and Shiites that have been inflamed by the civil war in neighboring Syria.

Lebanon’s health ministry said at least four people were killed in the suburb, Haret Hreik, and more than 70 were wounded. The state-run National News Agency said that human remains were found in a car near the blast site but that authorities had not determined whether they belonged to a suicide bomber.

The explosion came six days after a car bomb killed a prominent member of the Future Movement, Hezbollah’s main political rival, who had openly criticized the group. And it came a day after reports of the arrest of a Saudi militant who leads a Lebanon-based affiliate of Al Qaeda, the Abdullah Azzam Brigades, which claimed responsibility for a suicide bombing in November near the Iranian Embassy in Beirut. Iran is an ally of Hezbollah.