Turkey’s foreign minister has hit back at Donald Trump over his threat to economically devastate the country if it follows through on a planned operation against Kurdish forces in northern Syria, saying Ankara will not be intimidated by its Nato ally.

“We have said repeatedly we are not scared of and will not be intimidated by any threats,” said Mevlüt Çavuşoğlu in televised remarks from Ankara on Monday, before rebuking the US president for using Twitter for sensitive diplomatic matters.

“Strategic partners, allies, do not hold discussions via Twitter, via social media,” Çavuşoğlu told reporters.

Trump said in tweets on Sunday that Turkey would face economic consequences if it attacked Kurdish fighters in Syria. Ankara views them as members of a Kurdish group outlawed in Turkey as terrorist organisation.

He also suggested the creation of a 20-mile (32km) “safe zone”, without detailing its location or who would create, enforce or pay for this area. Çavuşoğlu was warmer towards the idea, saying Turkey was not against the idea of a buffer zone on the Turkish-Syrian border.

Trump and Recep Tayyip Erdoğan discussed the establishment of a safe zone and ongoing cooperation as US forces withdraw from Syria in a phonecall on Monday evening, the Turkish president’s office said.

The Turkish lira fell by as much as 1.6% to 5.5450 against the US dollar on Monday after the dispute.

Trump’s remarks were also criticised by the Turkish presidential spokesman, İbrahim Kalın, who vowed that Turkey would protect its security interests. He said the US president should respect their alliance.

“Terrorists can’t be your partners and allies. Turkey expects the US to honour our strategic partnership and doesn’t want it to be shadowed by terrorist propaganda,” he said.

The latest spat between Washington and Ankara comes after Trump’s surprise decision last month to withdraw the US’s 2,000 troops on the ground in north-east Syria, who are partnered with Kurdish forces in the area in the fight against Isis and act as a buffer with Turkey.

The announcement was widely criticised as a betrayal of the US’s Kurdish partners, but was welcomed in Turkey. The move in theory removes one of the major points of friction between the two Nato allies, but subsequent confusion over the timeline and comments from US officials including the secretary of state, Mike Pompeo, in support of protecting Kurdish fighters have frustrated Ankara.

Speaking in Riyadh on Monday, Pompeo said Trump’s latest warning to Turkey did not alter the plan for a full US withdrawal from Syria or the handing over of the job of destroying the last remnants of Isis to the Turkish military.

Mike Pompeo, the US secretary of state, meets Saudi officials as he arrives in Riyadh. Photograph: Reuters

Asked what Trump meant by economic devastation, Pompeo told reporters: “You’ll have to ask the president. We have applied economic sanctions in many places. I assume he is speaking about those kinds of things.” He said he had not spoken with his counterparts in Ankara since Trump made the comments.

A diplomatic crisis last year, when Trump imposed sanctions on two of Erdoğan’s ministers and raised tariffs on Turkish metal exports, helped push the Turkish lira to a record low in August.

Washington-Ankara relations have been on something of a rollercoaster in recent months, after the death of the Saudi journalist Jamal Khashoggi in Istanbul and the release of jailed US pastor Andrew Brunson, which suggested a significant thaw.