Syrian state TV reported Friday that the leader of the al-Qaeda-affiliated rebel group Jabhat al-Nusra, also known as the Nusra Front, was killed.

Mohammed al-Jolani, according to the report, was killed in unknown circumstances in in the coastal province Latakia.

Syrian TV did not say when or give other details. Opposition groups had no immediate comment on the report.

Rebels have gained footholds in mountainous regions of Latakia, which is largely loyal to President Bashar Assad.

Al-Jolani's death has been reported in the past by Lebanese and Iranian media but this is the first time Syrian state-run TV has reported it, according to Walla News.

The Nusra Front, and the Islamic State of Iraq and the Levant — both al-Qaeda-linked Islamist groups — are two of the active rebel factions fighting forces loyal to Assad.

Both have fought other rebel brigades to seize strategic border areas, and are also battling Kurdish fighters in northern Syria.

The Nusra Front, founded in January 2012 — 10 months into the Syrian crisis — was designated as a terrorist organization by the US State Department in December 2012. It has claimed responsibility for many of the deadliest suicide bombings targeting regime and military facilities – over 600 attacks across Syria, including 40 suicide bombings, according to the State Department.

The presence of Islamic extremists among the rebels is one reason the West has not equipped the Syrian opposition with sophisticated weapons, such as anti-aircraft missiles.

In recent months, Jabhat al-Nusra has been eclipsed to a degree by the rising power of the Islamic State of Iraq and the Levant..

The Syrian civil war began as a peaceful revolution in March 2011. The deadly conflict has since claimed the lives of over 100,000 people and has displaced millions, according to UN figures.