US clashes with Turkey at NATO talks
A US spokesman would not confirm or deny the details of Pompeo's participation in Tuesday's foreign minister's videoconference, but several well-placed sources described the exchange as heated.
Turkey has faced criticism over its stance in a maritime territorial dispute with fellow NATO member Greece and its support for Azerbaijan in the recently revived conflict with Armenia over a disputed enclave.
European warships are also attempting to enforce an arms embargo on war-torn Libya, where Turkey is supporting the Tripoli government.
Some NATO and EU members – with the notable exception of France – have been cautious about criticising President Recep Tayyip Erdogan's government, for fear of escalating the crises.
But Pompeo, attending one of his last NATO meetings – as US President Donald Trump's adminstration will leave office next month – did not hold back in an exchange with Turkish Foreign Minister Mevlut Cavusoglu.
'Short but clear'
Senior participants told AFP that Pompeo accused Turkey of playing into the hands of NATO's rival Moscow by buying the Russian S-400 missile defence system, despite the allies' opposition, one participant told AFP.
And he urged Ankara to behave more like an ally, accusing it of thwarting efforts to build unanimity for vital reforms, according to those taking part.
"His intervention was quite short, but very clear," the senior official told AFP, speaking on condition of anonymity to describe a closed-door diplomatic discussion.
Another source familiar with the talks said the exchange was "punchy".
The official US State Department readout of the meeting did not mention Turkey, but Pompeo has been critical of Ankara in recent weeks.
Washington's top diplomat was in Paris last month, and told the daily Le Figaro that he had spoken with President Emmanuel Macron and agreed that Turkey's recent actions had been "very aggressive".
Germany is leading a diplomatic outreach to Turkey to try to resolve some of the European capitals' concerns, and NATO has set up a "deconfliction mechanism" to head off accidental clashes with Greek forces.
But some EU members are also pushing for economic sanctions.
Macron clashed with Erdogan at December's NATO summit in London, but the Turkish leader was reportedly defended by Trump.
At this week's talks the American envoy was less protective of Turkey, and France and Luxembourg joined Pompeo in going on the attack.
EU members will decide at a summit on December 10 whether to begin the process of applying sanctions against Turkey for violating Greek waters to search for gas or breaching a UN arms embargo on Libya.
Read more: Turkey research ship returns home as possible tough EU sanctions loom
"Ankara no longer has a lot of support in the EU, as the Turks have not adopted any more positive behaviour since the adoption of the double strategy in October," an EU official told AFP.
The double strategy – German led diplomacy backed by the threat implied by the EU drawing up lists of potential sanctions targets – still has the support of Germany's Chancellor Angela Merkel.