Turkey’s position in Nato came under fire at a London meeting to mark the alliance's 70th anniversary on Tuesday as US President Donald Trump warned Ankara would forfeit billions from cancelled weapons purchases after installing a Russian air defence system.
The US leader spoke out on Turkey as he met with international leaders and those from Nato in the British capital.
Anger over the purchase of the S-400 missile defence system from Russia has increased after Turkey vetoed defence planning in Baltic states until the Kurdish YPG are designated terrorists.
Officials having been trying to resolve the impasse.
"I will not promise that but what I can say is that we are working on that," Mr Trump said. "But it is not like Nato doesn't have a plan to defend the Baltic countries."
After meeting Nato Secretary General Jens Stoltenberg, Mr Trump said Ankara had lost “billions” over forward purchases of the F35 fighter jet.
The jet order was cancelled after Ankara installed the Russian-made S-400 system, which is incompatible with Nato's air control.
Mr Stoltenberg confirmed the alliance was formally split over the YPG designation but added officials hoped for a communique on Wednesday at the end of the talks.
Recep Tayyip Erdogan, the Turkish President, said he would block defence proposals for Poland and the Baltic nations until the alliance supported Ankara's concerns about the Kurdish fighters who were allies with the West in the fight against ISIS in Syria.
Gulnur Aybet, an adviser to Mr Erdogan, told a Nato gathering that her government had a right to defend its position within the alliance.
“On the Baltics and Poland, this is an internal Nato matter,” she said. “I don’t think it should be leaked to the press. This is not at the approval stage.
"Some documents of similar sort for Turkey had framed the YPG as a terrorist group, but then one member objected to that and they have blocked.
“These are Turkey’s defence plans stopped, too. You cannot have one debate and address the security plans of one ally and not address another.”
The presence of Russian defences inside a Nato country is also unresolved.
The US and other allies say the system is not compatible with Nato forces, and could compromise the F-35 fighter jet programme and assist Russian intelligence.
French President Emmanuel Macron said Nato must demand clarification from Turkey about its commitment to the alliance.
Mr Macron, whose relationship with Mr Erdogan has become increasingly tense, said it was not possible for Turkey to be a member of Nato while using the system.
"How is it possible to be a member of the alliance, to work with, to be integrated and buy things from Russia?" he asked.