Who are the Kurds? A Middle Eastern people with 'no friends but the mountains'

Kurdish Peshmerga fighters and commanders overlook Islamic State group positions during heavy fighting in Bashiqa, east of Mosul, Iraq, on Nov. 7, 2016.

President Donald Trump made an abrupt decision this week to withdraw U.S. troops from the border between Turkey and Syria, a move that cleared the way for Turkey to launch a military offensive Wednesday into Kurdish-controlled parts of Syria.

"Our mission is to prevent the creation of a terror corridor across our southern border, and to bring peace to the area," Turkey's President Recep Tayyip Erdogan said Wednesday, announcing an invasion that has been widely criticized.

Trump said his administration would continue to monitor the situation closely. 

Turkey views the Kurds as terrorists but U.S. military planners and other western nations see them as partners in fighting the Islamic State, also called ISIS. 

Here's a brief explainer about the people who, as the saying goes, have "no friends but the mountains"

Who are the Kurds?

The Kurds are an ethnic minority group found in the Middle East and in the mountainous Caucasus region between Europe and central Asia. They number between 25-40 million, according to estimates by the CIA Factbook, and straddle territory that belongs to Armenia, Iran, Iraq, Turkey and Syria. The Kurds have never formally obtained a permanent state for various reasons to do with the way the British and French carved up the region in the wake of World War I and the fall of the Ottoman Empire. 

What doesn't Turkey like about the Kurds?

The Kurds have many different political groups and militias spread across the region. The Kurdistan Workers' Party, or PKK, has been fighting for autonomy in eastern Turkey for three decades. The PKK has carried out bombings and other assaults in Turkey. Turkey's government views the People's Protection Unit, or YPG – a Kurdish militia that dominates the U.S.-backed Syrian Democratic Forces, or SDF – as aligned with the PKK. The SDF has been leading the fight against the Islamic State.

Why is Trump pulling troops out now?

The U.S. president tweeted Monday that he had been elected on "getting out of these ridiculous endless wars," adding that "Turkey, Europe, Syria, Iran, Iraq, Russia and the Kurds will now have to figure out the situation."

Trump's announcement followed a call with Turkey's President Recep Tayyip Erdogan. Erdogan has previously made clear his determination to invade Kurdish-controlled territory in Syria to hunt YPG militants he considers a threat to his country, but to also establish a "safe zone" – a phrase Erdogan used at the recent United Nations General Assembly in New York – along Turkey's border with Syria. Around 3.6 million Syrian refugees from that nation's civil war live in camps along this border and Erdogan wants them resettled, possibly in this "safe zone."

What has the reaction been to Trump's decision?

Pretty damning for the U.S. president as he also faces an impeachment inquiry.

Mustafa Bali, a spokesman for the SDF, tweeted Monday that "We are not expecting the US to protect NE #Syria. But people here are owed an explanation regarding security mechanism deal, destruction of fortifications and failure of US to fulfill their commitments." The U.S. only has about a 1,000 troops across Syria, according to the U.S. State Department, but the SDF – not to mention other U.S. coalition forces battling the remnants of the Islamic State in the region, such as from Britain and France – view U.S. participation as essential to preventing a resurgence of the Islamic State.

There are also concerns that if Turkey attacks the SDF it could lead to further displacement of refugees and, perhaps more worryingly still, lead to a chaotic and dangerous situation for Kurdish-run detention centers that are holding thousands of captured Islamic State fighters and their families including Hoda Muthana, an American who exhorted Americans to commit mass murder and terror attacks.

'A reckless gamble': Four reasons critics decry Trump's 'impulsive' Syria withdrawal

Graham: 'We can’t abandon the Kurds now'

Amid growing bipartisan condemnation over the move, Trump tweeted Tuesday that "We may be in the process of leaving Syria, but in no way have we Abandoned the Kurds, who are special people and wonderful fighters." Trump has also threatened to destroy Turkey's economy if Erdogan launches an attack on Kurdish fighters. 

"#Syria isn’t about neocons or hawks, it’s about reality. The Kurds were lead ground force against ISIS & currently hold 1000’s of ISIS killers in jail. Abandoning them is morally repugnant,stains our nations reputation & could lead to 1000’s of ISIS killers back on battlefield, " Sen. Marco Rubio, R-Fla., tweeted Tuesday. 

U.S. and Kurds: A history

The U.S. and others have turned their backs on the Kurds before. 

In fact, the Kurds have a popular saying – "no friends but the mountains" – that reflects the various doomed alliances they have made with world powers since the fall of the Ottoman Empire. Invariably, the Kurds have been on the sharp end of betrayal. 

Among the more blatant examples involving Americans took place during the Iran-Iraq War (1980-1988) when President Ronald Reagan's administration tolerated an offensive against Iraqi Kurds by Iraq's leader Saddam Hussein that killed 100,000 Kurds and involved perhaps the first recorded use of chemical weapons by a state against its own people. Reagan knew about Hussein's use of chemical weapons but was concerned that if he moved against him it could work in favor of the U.S.'s archenemy, Iran. 

More than a decade later, during the Iraq War (2003), President George W. Bush cited Hussein's treatment of the Kurds as one of the reasons for the U.S. invasion. Kurdish fighters alongside Americans helped rid Iraq first of Hussein, then loyalists from his ruling Baa'thist party, before moving on to play a role in tackling al Qaeda in Iraq and driving the Islamic State out of key strongholds in Iraq, such as Mosul.

But this loyalty has not consistently been repaid. 

In 2017, Iraqi Kurds overwhelmingly voted in favor of independence. However, then-U.S. Secretary of State Rex Tillerson said "the vote and the results lack legitimacy" and that the U.S. will "continue to support a united, federal, democratic and prosperous Iraq."  

More: Trump, facing scathing criticism over Syria pullout, warns Turkey that invasion is a 'bad idea'

This article originally appeared on USA TODAY: Syria pullout: As Donald Trump defends move, who are the Kurds?