Dramatic new pictures have emerged of the moments after an oil line exploded in the embattled Syrian town of Homs.
Activists say the city has been under near-constant attack by government forces for almost two weeks.
On Wednesday an explosion at a nearby oil line resulted in a huge cloud of fire and smoke which blanketed the city.
New pictures released of the explosion showed fireballs rising into the air as a man identified by the AP as a citizen journalist and activist stands close by.
Activists say that the pipeline had been hit by government shells, but state media said it was an "armed terrorist group" who were responsible.
It was not possible for the Huffington Post UK to independently verify the claims.
Meanwhile, the New York Times quoted US officials and diplomats blaming two recent attacks in the country on Al Qaida.
"It appears to be a very complicated mixture of networks that are fighting the Syrian government, including individuals associated with Al Qaida in Iraq,” Seth G. Jones, who is a political scientist at the RAND Corporation, told the newspaper (read the full story here).
Also on Thursday China said it was sending an envoy to the country in an attempt to negotiate a peaceful solution.
Deputy Foreign Minister Zhai Jun will visit Damascus on Friday, China said.
A similar effort by the Russian foreign minister Sergei Lavrov in January ended in little success, officials in the EU, UK and United States have argued.
China and Russia both vetoed a January resolution which called on Syrian president Bashar al-Assad to stand down and cease the violence against civilians.
According to activists almost 7,000 people have been killed in Syria since March.