President Donald Trump's decision to withdraw US forces from northeast Syria has pushed formerly US-allied Kurdish forces into the arms of Syrian President Bashar al-Assad and Russia.

Trump is apparently not concerned that the Kurds, who bore the brunt of the US-led campaign against ISIS, are now looking to Moscow instead of Washington.

Trump on Monday said anyone, including Russia and China, who wants to protect the Kurds in Syria is "good" with him.

The president tweeted: "Anyone who wants to assist Syria in protecting the Kurds is good with me, whether it is Russia, China, or Napoleon Bonaparte. I hope they all do great, we are 7,000 miles away!"

Visit Business Insider's homepage for more stories.

President Donald Trump's decision to withdraw US troops from northeast Syria has handed a big victory to Moscow — and he's apparently fine with that.

Trump on Monday said anyone, including Russia and China, who wants to protect the Kurds in Syria is "good" with him.

By withdrawing US troops from northeast Syria earlier this month, Trump opened the door for a Turkish military incursion against Kurdish forces who played a key role in the US-led fight against ISIS.

The presence of US forces in northeast Syria was the only thing preventing Turkey, a fellow NATO member, from launching the invasion into the region. Once Trump withdraw US troops, Turkey launched the incursion within three days.

Kurdish forces referred to the move as a "stab in the back." Meanwhile, US lawmakers and former officials promptly warned Trump his decision would create a security vacuum that US foes could take advantage of.

Read more: Trump hits Turkey with sanctions over military operation against Kurds in Syria

Roughly a week after the Trump administration announced the withdrawal, the Kurdish-led Syrian Democratic Forces are already engaged in talks with Syrian President Bashar al-Assad's government with Russian involvement.

In short, forces that were allied with the US at the beginning of the month are now apparently moving toward aligning with US adversaries to thwart the Turkish assault.

"After the Americans abandoned the region and gave the green light for the Turkish attack, we were forced to explore another option, which is talks with Damascus and Moscow to find a way out and thwart these Turkish attacks," senior Kurdish official Badran Jia Kurd said. "This is a preliminary military agreement. The political aspects were not discussed, and these will be discussed at later stages."

Russia is allied with Assad, as well as Iran. Accordingly, any move that benefits Damascus also generally benefits Moscow and Tehran. After years of the US, Russia, and Iran vying for supremacy in Syria, Trump has decided to step aside.

To put it another way, Trump has essentially gifted one of America's strongest partnerships in the Middle East to Russian President Vladimir Putin.

Trump on Monday afternoon signaled he's OK with these developments.

The president tweeted: "After defeating 100% of the ISIS Caliphate, I largely moved our troops out of Syria. Let Syria and Assad protect the Kurds and fight Turkey for their own land. I said to my Generals, why should we be fighting for Syria and Assad to protect the land of our enemy?"

Trump added: "Anyone who wants to assist Syria in protecting the Kurds is good with me, whether it is Russia, China, or Napoleon Bonaparte. I hope they all do great, we are 7,000 miles away!"