Turkey President Recep Tayyip Erdogan’s spokesman said on Monday Turkey expected the United States to honor their strategic partnership after US President Donald Trump tweeted that “it will devastate Turkey economically if they hit Kurds”.

“Mr @realDonaldTrump It is a fatal mistake to equate Syrian Kurds with the PKK, which is on the US terrorists list, and its Syria branch PYD/YPG,” spokesman Ibrahim Kalin wrote on Twitter in response to Trump’s tweet.

US President Donald Trump warned Sunday that if Turkey attacks US-backed Kurdish forces in Syria, the United States will “devastate Turkey economically.”

Trump’s decision to pull American troops out of Syria has left the United States’ Kurdish allies vulnerable to an attack from Turkey. Ankara views the Kurdish forces as terrorists aligned with insurgents inside Turkey.

The US withdrawal has begun with shipments of military equipment, US defense officials said. But in coming weeks, the contingent of about 2,000 troops is expected to depart even as the White House says it will keep pressure on the Daesh network.

“Starting the long overdue pullout from Syria while hitting the little remaining Daesh territorial caliphate hard, and from many directions,” Trump tweeted. “Will attack again from existing nearby base if it reforms. Will devastate Turkey economically if they hit Kurds.”

Trump’s decision to leave Syria, which he initially said would be rapid but later slowed down, shocked US allies and angered the Kurds in Syria. It also prompted the resignation of Defense Secretary Jim Mattis and drew criticism in Congress. Sen. Jack Reed, a Rhode Island Democrat, called the decision a “betrayal of our Kurdish partners.”