Defense Secretary James Mattis said Friday that President Donald Trump has accelerated the international campaign against the Islamic State by directing U.S.-led coalition forces to surround enemy fighters in their strongholds before advancing to attack them.
"By taking the time to de-conflict, to surround, and then attack, we carry-out the annihilation campaign so we don't simply transplant this problem from one location to another," Mattis said during a Pentagon briefing.
Mattis said the tactical shift has severely undercut the ability of foreign fighters to escape and return home, noting that most ISIS fighters left in Iraq and Syria will die in those countries.
Chairman of the Joint Chiefs of Staff General Joseph Dunford said the flow of foreign fighters into Iraq and Syria has also drastically dropped. The Pentagon estimated that in 2015 there were 1,500 foreign fighters arriving in Iraq and Syria each month. Dunford said that number is now down to less than 100 per month.
Dunford attributed this in part to the Trump administration's relaxation of Obama-era restrictions on the movement of U.S. military advisers on the battlefield. The change has allowed American advisers to operate closer to the front-lines alongside partner forces.
The Pentagon said ISIS has lost more than 35,000 square miles in territory to U.S.-led coalition forces, none of which has been recouped by the terrorist group. Coalition air and ground operations have also destroyed 2,600 ISIS-held oil and gas targets, resulting in the group's lowest revenue levels since 2014.
Trump in April delegated greater authority to Mattis in the ISIS campaign, allowing him to launch certain operations without the immediate approval from the White House. Mattis said this change has resulted in Iraqi forces successfully surrounding ISIS strongholds in West Mosul and Tal Afar, leaving militants with "no escape."
"The campaign end-state remains the same—to destroy ISIS—but no longer will we have slowed decision cycles because Washington, D.C., has to authorize tactical movements on the ground," Mattis said.