'This is just chaos': Retired Marine general condemns Trump's decision to stand down as Turkey launches military attacks in Syria

• John Allen, a retired four-star Marine general, criticized President Donald Trump's decision to withdraw US troops as Turkey's military assaults northeastern Syria.
• "If we were going to draw a circle around a group of American troops who are more important right now to the stabilization of any place on the planet, it's that thousand troops," Allen told CNN on Wednesday.
• Allen commanded the US-led forces in Afghanistan and is now president of The Brookings Institute.
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Retired US Marine Corps Gen. John Allen criticized President Donald Trump's decision to stand down as the Turkish military launched an assault on northeastern Syria.

"This is just chaos," Allen said during an interview with CNN on Wednesday.

Allen, who commanded the US-led coalition force in Afghanistan and is now president of The Brookings Institute think tank, criticized Trump for pulling back a small contingent of US troops from the Syria-Turkey border ahead of the Turkish military operation.

Trump spoke with Turkish President Recep Tayyip Erdoğan by phone on Sunday, a call during which Erdoğan asked Trump to allow Turkey to establish a "safe zone" for Syrian refugees inside Syria, according to Washington Post columnist Josh Rogin.

On Sunday night, the White House announced US troops near the border would be shifted elsewhere, as Turkey moved "forward with its long-planned operation into Northern Syria."

The next day, Trump defended his decision on Twitter, saying US troops should only fight "where it is to our benefit, and only fight to win."

"The US has done far more than anyone could have ever expected, including the capture of 100% of the ISIS Caliphate," Trump added on Monday. "It is time now for others in the region, some of great wealth, to protect their own territory. THE USA IS GREAT!"

Allen characterized Trump's decision as an abrupt shift likely to have disastrous consequences for the region.

"We don't do strategy and we shouldn't be doing foreign policy by tweet," Allen told CNN. "And this is what you get when you have a single phone call between world leaders."

Read more: The general who led the fight against ISIS says Trump's new policy 'breaks that trust' after years of hard fighting

Allen noted that Kurdish forces, on whom the US relied heavily in the war against ISIS, would face significant losses against the Turkish military. Roughly 11,000 members of the Kurdish-majority Syrian Democratic Forces died fighting ISIS, according to some estimates, and thousands of ISIS fighters are held in prisons and camps guarded by Kurdish forces.

Turkey claims the Kurdish People's Protection Units, or YPG, and the SDF are a threat with links to the Kurdistan Workers' Party (PKK), a Turkey-based group that Ankara and the US, among others, have designated a terrorist organization.

"Once you push into an area like this, once you start using indirect fire, once you start drawing a lot of blood from an organization that has just been fighting now for a couple of years against the most abhorrent terrorist organization on the planet, the Islamic State, these people were bucking down to begin the process of the stabilization of that entire region," Allen said.

In addition to assistance fighting ISIS, the presence of about 1,000 US troops at the border has been viewed as a deterrent to potential Turkish incursions in the region.

"That's why those thousand American troops, if we were going to draw a circle around a group of American troops who are more important right now to the stabilization of any place on the planet, it's that thousand troops," Allen added.

Other former senior US military leaders have criticized the development. Former US Central Command commander and retired Army Gen. Joseph Votel expressed disappointment in a column, calling it an "abrupt policy" that appeared to "abandon our Kurdish partners."

Lawmakers from both parties have also denounced the move.

Read more: 'The President eats his own': Military veterans in Congress unload on Trump for abandoning a US ally in the ISIS fight

Republican Sen. Lindsey Graham of South Carolina, one of Trump's staunchest allies, urged the president "to change course while there is still time."

"Pray for our Kurdish allies who have been shamelessly abandoned by the Trump Administration," Graham said on Twitter. "This move ensures the reemergence of ISIS."

Democratic Rep. Seth Moulton of Massachusetts, a Marine combat veteran, described Trump as "a failure of a Commander in Chief who has no idea what it means to serve."

"This decision sends the message to our adversaries that America doesn't keep our promises and there will be no consequences for their dangerous behavior," Moulton tweeted. "This is a grave mistake that will cost lives."

Turkish aircraft began bombing northern Syria on Wednesday morning, according to unverified accounts from SDF forces.

Trump and White House officials say they are not endorsing nor taking part in the military campaign and threatened economic sanctions against Turkey.

"As I have stated strongly before, and just to reiterate, if Turkey does anything that I, in my great and unmatched wisdom, consider to be off limits, I will totally destroy and obliterate the Economy of Turkey (I've done before!)." Trump tweeted on Monday.