A powerful car bomb struck the southern Beirut stronghold of Lebanon’s militant Hizbollah group yesterday, killing 20 people, wounding 120 and trapping many others inside damaged buildings, witnesses and emergency officials said.

The blast, a month after another car bomb wounded more than 50 people in the same district of the Lebanese capital, came amid sectarian tensions over the intervention of Shi’ite Muslim Hizbollah against Sunni rebels in Syria’s civil war.

A Sunni Islamist group calling itself the Brigades of Aisha claimed responsibility for the attack and promised more operations against Hizbollah.

It was not immediately possible to verify the statement, made in an internet video.

“I don’t know what happened. It’s as if we were struck by an earthquake,” one young man at the scene said, bleeding from a wound to his stomach.

Health Minister Ali Hassan Khalil said hospitals across the capital admitted a total of 16 bodies and 226 wounded people.

At the heart of the site, where fires raged an hour after the blast, the twisted remains of a large van could be seen.

Many cars were engulfed in flames, the charred bodies of drivers and passengers still visible inside. The blast sent a column of black smoke above the densely populated area and the facades of several residential buildings were damaged.

Al Mayadeen TV said some people were trapped inside apartments at the scene, close to the Sayyed al-Shuhadaa (Martyrs) complex, where Hizbollah leader Sayyed Hassan Nasrallah often addresses his followers.

Residents of southern Beirut say Hizbollah, backed by Iran and Syria, had been on high alert and stepped up security in the area after warnings from Syrian rebels of possible retaliation for the group’s support for President Bashar al-Assad.

“I heard a huge explosion. It threw me several metres,” said a woman in her 50s who said she had been talking to her brother in his shop. “I don’t know what happened to my brother. I can’t find him.”

“This is the second time that we decide the time and place of the battle... and you will see more, God willing,” the Brigades of Aisha statement said, describing Hizbollah and Nasrallah as Iranian agents.

“We send a message to our brothers in Lebanon, we ask you to stay away from all the Iranian colonies in Lebanon... because your blood is precious to us,” a masked spokesman, flanked by two men brandishing rifles, said in the video.