A NATO investigation into a naval standoff between French and Turkish ships in June has been rated too sensitive to discuss in public and does not apportion blame, as Paris and Ankara wage a war of words, diplomats have told Reuters.
The issue underlines NATO's difficulties with Turkey, also at odds with Greece over energy rights and with the alliance's leader, the United States.
On June 10, a French frigate on a NATO mission tried to inspect a Tanzanian-flagged cargo ship suspected of smuggling arms to Libya.
France says the frigate was harassed by Turkish navy vessels escorting the cargo ship, and accuses Turkey of breaking a U.N. arms embargo. Turkey denies this, and says the frigate was aggressive.
It now seems unlikely that the investigation can resolve the spat. A NATO official confirmed the report had been finished, but declined further comment.
"It's been swept under the carpet," one European diplomat said.
Another said NATO's determination to keep Turkey onside, because of its military clout and strategic location, meant there was no willingness to point a finger.
And so both sides claim victory, and accusations continue to be traded.
French President Emmanuel Macron last week bemoaned the "unacceptable behaviour" of his Turkish counterpart Tayyip Erdogan's government. Erdogan retorted: "Don't mess with Turkey."
The men are also at loggerheads over Greece, which disputes Turkey's right to explore for hydrocarbons in waters claimed by Greece or Cyprus.
France has demonstratively joined Greek naval exercises.
Here too, NATO is trying to do what it can to prevent untoward incidents, through "deconfliction" talks.
"It's unclear if there will be a result in these negotiations," said a senior NATO official. "Every utterance from Paris, Ankara or Athens makes it even harder for allies to walk back from their positions."
Disputes with Turkey within NATO are not new.
Last year, Turkey for a time refused to back a defence plan for the Baltics and Poland unless NATO offered political support for Ankara's fight against a Syrian Kurdish militia backed by Washington.
Turkey's purchase of Russia's S-400 air-defence system also appeared to be a snub to the United States and other allies.
But it seems local tensions can for now be overlooked.
"Some of this is Macron wanting to be the big man in Europe, which is the same with Erdogan," said a U.S. envoy in Europe. "There is a solution to be had with the Turks."