Clashes, explosions as Islamic State seeks expansion in north Syria: monitor

The Syrian Observatory for Human Rights said the jihadists attacked the city of Marea, which lies along a key rebel supply route in Aleppo province leading north to the Turkish border.

"There were two car bombs on positions in and near Marea, which is controlled by Islamist militants and (Al-Qaeda affiliate) Al-Nusra Front," said Rami Abdel Rahman, head of the Britain-based Observatory.

Seven people were killed in the first explosion, which struck within Marea, and another eight died in the second, which detonated near the city, Abdel Rahman said.

He said IS fighters then clashed with Islamist groups, as well as their jihadi rival Al-Nusra Front, in Marea in a bid to "expand their reach" and edge closer towards the provincial capital of Aleppo.

Abdel Rahman had no immediate information on casualties from the fighting.

Although the extremist group had not claimed responsibility for the car bombs, it was suspected they were behind them too, he told AFP.

Marea lies 40 kilometres (25 miles) north of Aleppo city, Syria's former commercial hub but is now a city in ruins.

The country's conflict began in 2011 with peaceful protests but deteriorated into a complex civil war increasingly dominated by jihadist forces.