BEIRUT, Lebanon (CNN) -- A radical Sunni group has claimed responsibility for bombings that killed nearly two dozen people outside the Iranian Embassy in southern Beirut.
The Abdullah Azzam Brigades said the dual suicide blasts were "carried out by two heroes from the Sunni people of Lebanon." The al Qaeda-linked group is based in southern Lebanon.
"We warn Hezbollah that these attacks will continue until two objectives are met: first, the pullout of all fighters of Iran's party (Hezbollah) from Syria, and secondly, the release of all of our prisoners from the dungeons of tyranny in Lebanon," the group said.
At least 23 people were killed and 146 injured Tuesday in the twin bombings in front of the embassy, the Lebanese Health Ministry said.
Iran's cultural attache Sheikh Ibrahim Al-Ansari was killed in the attack, the Iranian ambassador to Lebanon told Hezbollah TV. Iran supports Hezbollah, a Shiite militant group based in Lebanon.
The blasts took place in an area largely dominated by Hezbollah, which has been sending fighters to support Syrian President Bashar al-Assad's regime.
More than 100,000 people have died in Syria's ongoing civil war, which pits al-Assad's Alawite-dominated regime against largely Sunni rebel fighters seeking an end to his family dynasty. Alawites make up an offshoot of Shia Islam, but the majority of Syrians are Sunni.
The Syrian crisis has led to sectarian violence across the border in Lebanon.
The dead also included two Iranian civilians who lived in a building close to the Iranian Embassy, Lebanon's National News Agency reported. The Lebanese army said one of the blasts was caused by suicide bomber on a scooter, and the other was caused by a suicide bomber in an SUV.
Stunned witnesses looked on as massive flames and pillars of black smoke leapt into the the sky. The fires burned out several cars parked on a nearby street.
At least six buildings were damaged, Lebanese Internal Security Forces said.
Iran's ambassador to Lebanon, Ghazanfar Roknabadi, said he had no doubt the embassy was the target of the two blasts, but he said any effort to thwart Iran's agendas would be unsuccessful.
"We have no fear when it comes to giving more martyrs in the line of duties," the ambassador told Hezbollah's Al-Manar TV.
Lebanon's acting prime minister, Najib Mikati, said the blasts were "a cowardly terrorist attack" and urged the Lebanese public "to exercise the utmost restraint because we are going through a very difficult phase," Lebanon's state news agency NNA reported.
Mikati also called the Iranian ambassador to check on his safety and express his condolences, NNA said.
-- CNN's Nick Paton Walsh contributed to this report.
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