Editors Note: This story has been updated.
The Islamic State claimed responsibility for a pair of suicide bombings that killed at least 35 people in Lebanon and injured more than 100 others Thursday. The group said in a statement posted online by its supporters that its members blew up a bike loaded with explosives in the southern Beirut suburb of Borj al-Barajneh and that when onlookers gathered, a suicide bomber blew himself up among them.
Borj al-Barajneh is a predominantly Shia neighborhood with a heavy Hezbollah presence, and home to a large Palestinian refugee camp.
The first bomb exploded around 6 pm local time. A crowd formed and several locals turned on their phones to record. Moments later the second bomb went off.
After the attacks, Interior Minister Nouhad Machnouk told Reuters that the bombers were on foot and wearing explosive vests. He also tweeted that: "We will not fail to prosecute the criminals wherever they are."
Images of the aftermath of the attack quickly spread online, showing mayhem and panic as rescue workers raced to aid survivors.
Since the Syria conflict erupted in 2011, Hezbollah has sent thousands of fighters to help prop-up Syrian President Bashar al-Assad, and fight the Islamic State and al Qaeda. Both Islamic State and al Qaeda have claimed responsibility for past suicide attacks inside Lebanon that targeted Hezbollah-dominated areas.
"This isn't new: it's not unexpected, it doesn't change Hezbollah's own strategies and calculation," said Paul Salem, the vice president for policy and research at the Middle East Institute. "But this does make Hezbollah and the Shiites in Lebanon pay a heavy civilian price for it's involvement in Syria".
Salem said the attacks are likely to harden Hezbollah's revolve.
"In many ways its reinforces Hezbollah's narrative that we have to fight these guys, if we don't' fight them in Syria they are going to come get us here in Beirut."
The bombing could very well stoke sectarian tension between Lebanon's Sunni and Shia populations. Prime Minister Tammam Salam urged his countrymen to resist that urge.
"We condemn this cowardly criminal act that can never be justified," he said. "We call on the Lebanese to be more watchful and united against strife."
Just hours after today's bombing, Islamic State supporters celebrated the attack on social media.
Watch VICE News' documentary The Islamic State Vs. Lebanon: