IS on the defensive, territory shrinking in Syria and Iraq: US official

Islamic State "is shrinking so they are very much on the defensive," Brett McGurk, US President Barack Obama's special envoy in the fight against Islamic State, told a news conference in Amman.

Islamic State controls the cities of Mosul in Iraq and Raqqa in Syria and is proving a potent threat abroad, claiming credit for major attacks in Paris in November and Brussels in March.

McGurk said that US-led coalition effort to capture Mosul and Raqqa was making progress.

"We are doing precision strikes in Mosul almost every day," he added. "There is constant synchronized pressure," he said.

McGurk cited a recent operation in which the coalition located and targeted Islamic State's cash stores in Mosul and "took out hundreds of millions of dollars out of their coffers."

This triggered a cash crunch that forced the militants to cut the pay of their fighters by half. He did not say when the operation took place.

Islamic militants' nervousness was evidenced by the recent public executions in the city's main square and a widespread clamp down on internet services in Mosul, McGurk said.

In Raqqa, McGurk said valuable intelligence gathered from a major trove of data and information obtained by US special forces in a raid in eastern Syria last year allowed the coalition to better target militants, McGurk said.

"We will be beginning over the coming weeks and months a pressure campaign on Raqqa in all its aspects," said McGurk.