US led air strikes kill at least 70 Islamic State fighters

US led air strikes against Islamic State killed at least 70 of its fighters on Tuesday in north and eastern Syria, a group tracking violence in the war said.

Rami Abdulrahman, who runs the Syrian Observatory for Human Rights, said the death toll was likely to be much higher. "The information is the numbers are bigger than that," he told Reuters by telephone.

He was citing casualties in the provinces of Raqqa, Deir al-Zor and Hasakah in northern and eastern Syria. Abdulrahman said the total number of dead and wounded was at least 300.

US President Barack Obama will make a statement on Tuesday following airstrikes for the first time against the militant group in Syria, according to the White House.

A White House official, speaking on background, said Obama will address the latest strategy to counter Islamic State in Syria.