Their caliphate in ruins, IS militants melt into the desert

BEIRUT -- Islamic State militants, routed from one urban stronghold after another in Syria, have been moving deeper into Syria's remote desert, where experts said they are regrouping and preparing their next incarnation.

The Sunni militants' self-proclaimed "caliphate" with its contiguous stretch of land -- linking major cities such as Syria's Raqqa and Iraq's Mosul -- may have been vanquished, but many agree this territorial defeat will not mark the end of IS.

Beyond the urban and inhabited areas lies the vast Syrian Desert, also known as Badiyat al-Sham, famous for its caves and rugged mountains. It encompasses about 200,000 square miles across parts of southeastern Syria, northeastern Jordan, northern Saudi Arabia and western Iraq.

The desolate landscape is a perfect hideout and a second home for many IS militants from the days before the birth of their caliphate. Experts estimate hundreds of thousands of troops would be needed to mount search operations -- and even more to put the desert under permanent control.

Once they melt into the desert, without an army of tens of thousands of supporters from dozens of countries, IS jihadis will resort to guerrilla-style attacks: scattered hit-and-run attacks and suicide bombings.

"They love fighting battles in the desert, and they will go back to the old ways," said Omar Abu Laila, a Europe-based opposition activist originally from Syria's eastern province of Deir el-Zour, which lies in the heart of Badiyat al-Sham.

IS leaders appear to have made contingency plans that involve precisely this -- regrouping in the desert and launching attacks, much like IS' predecessor, al-Qaida in Iraq, did for more than a decade after the U.S.-led 2003 invasion.

Some of those plans already are on display. In the eastern Syrian town of Mayadeen, a former IS stronghold, the militants pulled back and disappeared into the desert after only a few days of battle with Syrian government forces earlier this month.

The top U.S. envoy for the anti-IS coalition, Brett McGurk, said the Sunni militant group now is down to the last 10 percent of the territory it once held in Iraq and Syria.

The group still maintains some appeal for Sunnis, who complain of discrimination by Iraq's Shiite-led government and by Syrian President Bashar Assad's minority Alawite sect, an offshoot of Shiite Islam.

IS also will look to buy time and benefit from political and other conflicts --such as this month's clashes between Iraqi and Kurdish forces after the Kurdish independence referendum. That fighting already has diverted resources from the war on IS, the top U.S. general in Iraq, Lt. Gen. Paul Funk, said last week.

Iraqi troops, Shiite militiamen and Kurdish forces have driven IS from nearly all of Iraq, but if they turn on each other, that could give the extremists an opening to regroup.

A similar dynamic threatens recent gains in Syria. The U.S.-backed Syrian Democratic Forces and Russia-backed government troops have been the most effective in the fight against IS but are waging parallel offensives in Deir el-Zour that could bring them into conflict with each other.

Gen. Joseph Dunford, chairman of the U.S. Joint Chiefs of Staff, called the SDF's liberation of Raqqa an "inflection point" in the fight against IS, but warned the coalition needs to stay focused.

"ISIS is on their heels right now, and our job is to make sure they don't recover," Dunford said, using an alternative name for the group.

Experts say that will be difficult.

The group's predecessor, al-Qaida in Iraq, was almost crushed in 2007 by U.S. and Iraqi forces. But after the Americans withdrew from Iraq in 2011, the militants regrouped, emerging stronger than ever in the summer of 2014, when they conquered large areas of Syria and Iraq.