The U.S.-led military coalition against the Islamic State in Iraq and Syria (ISIS) expects to begin a new phase in the near future in Syria, led by rebel groups it is supporting, according the coalition's spokesman on Wednesday.

"The next phase is about to start here sometime in the near future. And I believe what you're going to see is Syrian-Arabs bringing additional and renewed pressure on ISIL in the vicinity of Raqqa. And it's going to be because of the ammunition that we gave them," said Army Col. Steve Warren, using an alternative acronym for the extremist group.

ADVERTISEMENT

As far as when the new offensive would begin, he added, "It's our understanding that there's a planning process and generation of combat power. So, I think what we're going to see is the Syrian-Arabs will begin to place pressure on ISIL in that region, here in the very near future."

The U.S. about a week ago airdropped about 50 tons of ammunition to the so-called Syrian Arab Coalition, which is comprised of about a dozen rebel groups the U.S. has vetted the leaders of and has worked with in the past.

That ammunition has been distributed, Warren said.

The U.S. earlier this month suspended its plan to train and equip Syrian rebels outside of Syria and send them back to fight ISIS. Instead, the U.S. is simply vetting the groups' leaders and distributing equipment through the leaders to their group members, which number approximately 5,000.

Warren said the coalition was "very confident" the ammunition has been distributed but added that it has also asked the groups' leaders to send pictures or some kind of proof to show that it has been received.

Under the previous U.S. program, it was discovered that some rebels trained and equipped by the U.S. had handed over some of their equipment to al Qaeda's affiliate in Syria, the Nusra Front.

Warren said the coalition had exfiltrated about 20 of the leaders to another location, where it spent one week familiarizing them with the new program, gave them instructions and infiltrated them back into Syria and gave them ammunition.

The U.S. is not exactly clear how many groups there are in the coalition.

"There's 10 to 12. Some of them, it's hard to tell, exactly. But there's no more than 12," he said.

Warren said the number of fighters in the coalition "will need to be beefed up" in order to take back Raqqa.

"Five thousand is probably not enough to do it, I wouldn't think," he added.

Warren said the coalition would continue to work with the Kurdish Peshmerga, as with the offensive to take back Kobani, but said it was unknown whether they would move south into Arab-controlled areas.

"Whether or not Kurdish fighters are willing to move that far south, frankly, is an unknown at this point," he said. "But we do know that Syrian-Arabs are ready. They're willing. And now that we've given them ammunition, [they are] able to conduct operations and place pressure on Raqqa."

Meanwhile, about 200 miles to the west, the Syrian regime, supported by Russian airstrikes, has been increasing their activities around Aleppo in the last two weeks, Warren said.

The U.S. earlier this week signed an agreement with Russia on the protocols of air safety to help U.S. and Russian air forces avoid any mid-air accidents.

So far, the Russians have conducted about 140 airstrikes in Syria — a fraction of which have targeted ISIS, Warren said.

Russia began airstrikes in Syria on Sept. 30 to shore up its ally Syrian President Bashar Assad's grip on power in the country. Although Moscow said the campaign was to target ISIS, it has mostly targeted anti-regime rebels — including some who have worked with the CIA.

"We continue to believe that Russia's strategy in Syria is counterproductive and will exacerbate the instability there," Warren said.