DAMASCUS, Oct. 29-- Over 30 Syrian troops were killed during overnight clashes with the Islamic State (IS) terror group near a key gas field in the country's central province of Homs, an oppositional monitoring group reported Wednesday.

The soldiers were killed during intense clashes that erupted overnight near al-Shaer natural gas field in eastern countryside of Homs, said the Syrian Observatory for Human Rights. It said the IS fighters are advancing into the area where they captured three gas wells on Tuesday.

The al-Shaer natural gas field was captured by IS militants on July 17, but Syrian troops recaptured it on July 26.

The IS, previously known as the Islamic State in Iraq and the Levant, has self-proclaimed an Islamic Caliphate in areas striding Syria and Iraq. It has also succeeded in capturing almost of the oil fields in the oil-rich province of Deir al-Zour in eastern Syria on the borders with Iraq.