While NATO has refused to get involved, the United States has stepped into the simmering troubles between Greece and Turkey before it reaches a conflict level to find a diplomatic solution that hasn’t worked yet.

Deputy Assistant Secretary of State for European and Eurasian Affairs Matthew Palmer told Greece’ state-run Athens-Macedonian News Agency (ANA-MPA) that, “We are working with our allies and partners to promote dialogue, to promote the responsible management of areas where disagreements have been reported and to work to de-escalate points of friction before they evolve into crises.”

That happened during a webinar hosted by the German Marshall Fund of the United States during which he described repeated violations of Greek airspace by Turkish fighter jets as “challenges,” in carefully-worded language designed not to offend either country at all.

“It is something we have been working on for years and many of these friction points have been around for a long time,” Palmer reportedly said without explaining why nothing has been resolved if the US has been working on it for years nor explaining what’s been done.

He spoke as tension has grown on the northern land border along the Evros River where Turkey in February and March tried to get 10,000 migrants across before Greece closed its side and sent riot police and Army units to repel them.

Turkey is also letting human traffickers continue sending refugees and migrants to five Greek islands near the Turkish coast, more than 38,000 being held in detention centers and camps that human rights groups said are unfit for them.

Palmer reportedly referred to a visit he carried out to northern Greece in March, saying that he had “encouraged Turkey to reduce this tension,” at the time. It didn’t work.