Cairo, Aug 22 (IANS/EFE): At least 70 members of the Islamic State (IS) Sunni extremist organisation have been killed in two days of clashes with the Syrian Army over al-Tabaqa military airport, the only bastion still in the hands of the government in al-Raqa province in northern Syria, the Syrian Observatory for Human Rights (SOHR) said on Friday.

The London-based NGO said dozens of IS militants were also injured in the fighting with Syrian forces and some of them are in serious condition.

The IS had announced Thursday its rapid advance in the area after launching an operation to take control of the airport.

But a Syrian military source told the SANA news agency that government troops are still controlling the airport.

The Sunni extremist organisation last June proclaimed an Islamic caliphate in areas under their control in Syria and Iraq.

The human rights office of the UN reported Friday that at least 191,369 people have been killed in the Syrian armed conflict between March 2011 and April this year.