The current strategy of the United States and its allies in the fight against the Islamic State is unlikely to succeed and more international coordination is needed, said experts.

In the past few months, the IS has not only repeatedly hit the headlines with online execution videos, it has also captured large swathes of land in Iraq and Syria.

The militant group now controls some 300,000 square km of land and the number of its fighters surged to above 100,000, posing severe threats to regional security.