Defense Secretary Jim Mattis said last week that President Trump’s strategy against the Islamic State in Iraq and Syria is different from former President Obama’s in multiple ways, despite detractors saying little was different.

In an off-camera question and answer session with reporters at the Pentagon on Friday, Mattis described how Trump’s strategy was different in four ways.

First, the president has delegated more decisions down, which led to an accelerated campaign, he said.

“That’s how you exploit or pick up the tempo of operation. He did that in order to do what he said he wanted done, an accelerated campaign,” Mattis said.

Second, Trump’s strategy seeks to envelop and annihilate ISIS, versus pushing them to other places, he said.

Mattis said this was so that “foreign fighters can’t get back home again to cause their mayhem.”

Third, the Trump administration got more international partners involved, to carry more of the financial burden, he said.

“Basically, we are right now not resource-constrained due to international donors in our efforts to help the people, for example, in Mosul and stuff,” he said.

Fourth, there are more nations providing military support, Mattis said.

“So, broaden the international coalition both in military and in donors, delegating and speeding up, accelerating the campaign, and surround/annihilate — surround/envelope and then work to annihilate this enemy so they don’t get home again with all the havoc they create,” he said.

“So, there’s four areas. That at least gives you something so you understand what changed,” he added.

So far, the new strategy, which was announced by Mattis in May, has seen success. This month U.S.-backed Iraqi forces recaptured Mosul, ISIS’s stronghold in Iraq.

The terrorist group had held the city for more than two years, since the summer of 2014 when it swept into Iraq from Syria, capturing large swaths of territory and sending Iraqi forces fleeing.

Iraqi forces are now turning their attention to other cities where pockets of ISIS fighters still exist.