ISIS took advantage of both the drawdown of US troops from northeastern Syria and the Turkish incursion to regroup and could prepare new attacks on the West, a report from the Pentagon said.
"ISIS exploited the Turkish incursion and subsequent drawdown of US troops to reconstitute capabilities and resources within Syria and strengthen its ability to plan attacks abroad," the Department of Defense Office of Inspector General said in a report released Tuesday.
President Donald Trump said on October 6 around 1,000 US troops were leaving northeast Syria, where they had kept an uneasy peace between neighboring Turkey and Syrian Kurdish fighters.
Trump's move allowed an incursion by Turkey dubbed Operation Peace Spring aimed at destroying Kurdish fighters, who had led the fight against ISIS and run jails for captured extremists in their effectively autonomous area in northern Syria.
Trump, who faced a backlash from Congress, including among key Republicans, has changed course several times, eventually announcing that a residual force would remain in Syria to protect oil fields.
The Office of Inspector General, which is an independent investigative arm, said that ISIS "will likely have the 'time and space' to target the West and provide support to its 19 global branches and networks.
In the long run, it "will probably seek to regain control of some Syrian population centers and expand its global footprint," the inspector general added, citing information provided by the Defense Intelligence Agency (DIA).
Meanwhile, the death of ISIS leader Abu Bakr al-Baghdadi, who was killed during a raid conducted by US special operations forces in Syria on October 26 "would likely have little effect on ISIS's ability to reconstitute," the DIA said, according to the report.
Already the terrorist group has "has activated sleeper cells to increase attacks" against the Kurdish-led fighters of the Syrian Democratic Forces, whom the United States relied upon in the fight against ISIS.
The report states that US forces in Syria continue to arm SDF fighters but have stopped training them. By the end of the third quarter, the SDF had 100,000 fighters, according to the document.