A key member of the Syrian opposition has accused the Damascus regime and its allies Iran and Hezbollah of being behind a bomb attack that killed a Lebanese politician in Beirut.
The powerful car bomb in the heart of the Lebanese capital on Friday killed six people, including Mohammad Chatah, a leading critic of Syrian President Bashar al-Assad's regime.
"The murderers... are the same ones that kill and continue to kill Syrians in Qusayr, Qalamoun, Ghouta, Aleppo, Homs and Idlib," said the Syrian National Council (SNC), the largest member of the umbrella National Coalition opposition grouping.
"They are undoubtedly the alliance between the Iranian and Syrian regimes and their agents in Lebanon led by the sectarian and fanatical militia Hezbollah," the SNC said in a statement issued overnight.
Hezbollah, a powerful Shiite movement, has sent troops to back the Assad regime in its war with rebels who have been fighting to oust his regime since a deadly crackdown on democracy protests in 2011.
"This bloody alliance... proves every day that it is the main source of terrorism and extremism which threatens the security and stability of the region," said the SNC.
Chatah, 62, was killed in Friday's blast as he headed to a meeting of Lebanon's Western-backed March 14 coalition that has supported the Sunni Muslim-led rebels in Syria.
Lebanese state media said more than 50 people were wounded and over 10 buildings badly damaged in the bombing, which officials said was caused by 50-60 kilograms (110-132 pounds) of explosives.
March 14 implied Damascus and Hezbollah were behind the attack without naming them, saying "the criminal is the same, he who is thirsty for the blood of Syrians... he and his Lebanese allies".
Hezbollah said the attack was aimed at destroying "national unity".
The Syrian conflict has cost an estimated 126,000 lives and displaced millions of people since it broke out in March 2011.