(CNN) Secretary of State Rex Tillerson met for more than three and a half hours of tough discussions with Turkish leaders in an attempt to ease increasing tensions with a key NATO ally -- but without a translator or policy aides.

The meeting with Turkish President Recep Tayyip Erdogan and Foreign Minister Mevlut Cavusoglu, who translated, was highly unusual because Tillerson reportedly wasn't accompanied by an American translator, any aides or a note-taker.

Asked about the unusual nature of the meeting, a State Department official said Tillerson has "met before with President Erdogan, and he's okay with the foreign minister doing the translation. They have a good, strong working relationship. "

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 Mr. Tillerson's points are delivered accurately and with the proper emphasis," said former State Department spokesman and CNN diplomatic and military analyst John Kirby.

Read More