As first reported in English media by Beirut-based Al Masdar News, the US Air Force dropped a bunker buster bomb on a cave in eastern Syria this week while wrapping up coalition operations against ISIS in the area of Baghouz, in Deir Ez-Zor province of eastern Syria.

The massive impact and explosion on the side of the Baghouz Mountains was caught on video as the coalition massive bomb targeted a cave reportedly used by Islamic State fighters who escaped the nearby US and Syrian Democratic Forces (SDF) successful liberation of Baghouz town, ISIS' last small territorial enclave.

File photo of a 5,000-pound "Bunker Buster" GBU-37 bomb, via Reuters

Bunker buster bombs have been more commonly used by US coalition forces over mountainous Afghanistan, but could now be increasingly in action in Syria to root out hard to access ISIS hideouts in Syria's Deir Ez-Zor region.

According to the Al-Masdar report:

The Islamic State has been holding out in the Baghouz Mountains for two weeks now, as they are currently encircled by the Syrian Democratic Forces (SDF) after losing the Baghouz Camp in eastern Deir Ezzor. Despite their presence at the Baghouz Mountains, the terrorists are all but finished in eastern Syria, especially after they were forced to concede the key towns of Hajin, Baghouz Tahtani, and Baghouz Fouqani.

A week ago the White House announced that all of ISIS caliphate territory in Syria has been “100 percent eliminated”.

Since liberating the last ISIS holdout of Baghouz, coalition forces have been pounding nearby mountains with airstrikes and heavy artillery, after remnant ISIS terrorists fled there instead of being among the bulk of those either fighting to the death or surrendering.

It doesn't look like the escaped terrorists are fairing too well, considering the impact size of the bunker-busting bomb in the video.

Watch the US Air Force drop a bunker buster bomb to destroy an ISIS mountain base:

#متداول | مقطع مصور يظهر غارة لـ #التحالف_الدولي على إحدى المغارات التي يتحصن بها مقاتلو تنظيم #داعش في #الباغوز. pic.twitter.com/xIgkITlHkl — Step News Agency (@Step_Agency) March 29, 2019

Meanwhile Russian officials over the past week have questioned whether ISIS' territorial caliphate has been really stamped out, saying previously, "the US announcement about the complete elimination of Daesh (ISIS) is not very convincing," according to state-run media.

Syria's envoy to the UN, Bashar Jaafari, also last week called Trump administration claims of a total ISIS defeat in Baghouz and the region a "bluff".

Regardless, the scenes of coalition bombings, Kurdish-led advances, and terrorist mass surrenders have been stunning over the past two weeks. Regardless it is clear that ISIS is in it's final days, not discounting the potential for an underground "endless insurgency" that may continue to rattle Syria and the region for years to come.

But still the months-long question remains: when are US troops actually coming home as promised by Trump on many occasions?

No one should hold their breath, especially as just days ago American defense officials confirmed that "many troops" will stay in Syria through 2019, which means about 1,000 or even the current 2,000 — as there's little evidence that any kind of major draw down is actually underway.