European Commission President Ursula von der Leyen and European Council President Charles Michel held their first talks Monday since a diplomatic gaffe in Turkey – dubbed "Sofa Gate" – laid bare tensions between the bloc's chiefs and major institutions.
Brussels has been rattled by the incident in Ankara last week that saw von der Leyen left without a chair at talks with male counterparts Michel and Turkish President Recep Tayyip Erdoğan.
European Council head Michel has faced flak for not appearing to support European Commission boss von der Leyen.
Michel offered his "deep regrets" to her at Monday's talks and assurances "such an incident must not happen again," his spokesperson said.
The council chief also stressed the need to "allow no one to divide the EU," the spokesperson added.
A commission source said von der Leyen had on Monday "made clear that she will never allow such a situation to arise again."
The former German defense minister was angered by the diplomatic slight in Ankara and is seeking to make sure that her role as head of the EU's executive is treated on a par with Michel's job running the body that brings together the bloc's 27 leaders.
The two EU chiefs are expected to meet Tuesday with heads of the European Parliament's political groupings to give an account of events in Ankara after a clamor from lawmakers for them to appear before the body.
On April 6, Michel and von der Leyen visited Ankara and met with Erdoğan as part of diplomatic efforts to improve relations between the bloc and Turkey.
In a video filmed ahead of the meeting, von der Leyen seems surprised as Michel is offered a chair next to Erdoğan, but she is left standing and seems unsure where to sit. She gestures with her right hand and says "ehm." She is eventually offered a seat on a nearby sofa.
Speaking to reporters Thursday, Turkish Foreign Minister Mevlüt Çavuşoğlu downplayed the incident, saying Turkey had satisfied all protocol requests from the EU side.
Turkish sources said Ankara did not receive any special requests before the meeting regarding the seating arrangement.
It is essential that the guest country's front delegation officials clearly express all of their demands regarding the visit for a successful meeting, they added.
It appears that Kirsi Punkkinen, the head of protocol of the European Council, was misled on the issue, they said, adding Punkkinen and von der Leyen's new diplomatic adviser Fernando Andresen Guimaraes had enough time to correct a possible mistake.
The EU officials claimed that the dining room, to which they were given access a few moments earlier, had the three chairs for the VIPs realigned for the benefit of the head of the European Commission.
Turkish authorities drew attention to the fact that the EU side's mishandling caused the issue.
Accordingly, the visiting delegation officials were invited to the working dining room as soon as the meeting started and they were provided with information about the arrangement there.
Before their meeting, Erdoğan asked both von der Leyen and Michel how they would like to have their photos taken, and they decided to take a photo together, it said.
However, the EU Council Press shared a photo of Erdoğan and Michel on Twitter cutting von der Leyen from the photo, it added.