US Secretary of State Rex Tillerson broke protocol by meeting Turkish President Recep Tayyip Erdogan without an American translator or policy aides, the media reported.

The meeting took place on Thursday for over three hours where the translation was done by Turkish Foreign Minister Mehmet Cavusoglu, reports CNN.

Tillerson was in Ankara to discuss growing tensions over the US military’s anti-Islamic State (IS) alliance with the YPG, a Kurdish militia in Syria.

Turkey has sent its troops into Syria to challenge the YPG and threatened to push into a town where US forces train Kurds and others. The Pentagon has responded forcefully, warning Ankara not to follow through.

Asked about the unusual nature of the meeting, a State Department official said that Tillerson has “met before with President Erdogan, and he’s okay with the Foreign Minister (Cavusoglu) doing the translation. They have a good, strong working relationship”.

Tillerson and Erdogan “engaged in a productive and open conversation about a mutually beneficial way forward in the US-Turkey relationship. We look forward to continued progress with our important NATO ally in conversations with Foreign Minister Cavusoglu tomorrow (Friday)”.

But former State Department officials said the meeting strayed from normal protocol.

“If the meeting is not conducted in English, it is foolhardy in the extreme not to have at his side a State Department translator, who can ensure that Tillerson’s points are delivered accurately and with the proper emphasis,” former State Department spokesman John Kirby told CNN.

“That Tillerson eschewed this sort of support in what he knew would be a tense and critical meeting with President Erdogan smacks of either poor staff work or dangerous naïvete on his part,” Kirby added.

Turkey was the last stop of Tillerson’s five-nation trip followed by his visits to Egypt, Kuwait, Jordan and Lebanon, CNN reported.

Tillerson’s meeting with Erdogan followed a Sunday visit by National Security Adviser H.R. McMaster.

After McMaster’s meeting with Cavusoglu warned that Turkey-US ties had hit a critical point and would either be repaired or be completely damaged.