Part of a pipeline running to an oil refinery in Homs, Syria blew up Thursday causing thick black smoke to hover about the city where protest against President Bashar al-Assad started in March.

The 1 a.m. explosion, according to the state news agency SANA, was caused by armed terrorist group, referring to anti-government protesters. However, activists in Homs point fingers to the government to justify the siege of the city and crackdown on protesters there.

The blown up section of the pipeline leads to Banias on the Mediterranean coast. Firefighters put out the fire and authorities stopped the flow of oil in the damaged pipeline and diverted it to other pipelines.

It was the third attack on a pipeline in Syria this year. In July, another part of the pipeline of the refinery in Homs was blown up.
Syria relies on the Homs refinery to process crude oil, which the European Union banned from being imported as punishment for the killing of anti-government protesters by Syrian security forces.

Protesters in Homs were again shot at by snipers on Thursday killing nine people, the British-based Syrian Observatory for Human Rights said, according to Reuters.

Protesters are demanding the resignation of Assad, whose family has ruled the country for 41 years, and his government. An estimated 4,000 people have been killed since the protest erupted in March, but the Assad administration denied killing protesters.

Canada, the EU and the U.S. have imposed economic sanctions on Syria for the killing of civilians. The Arab League also wants to impose sanctions on Syria unless it stops the killings and allow foreign observers into the country.