ANKARA - Turkey will block NATO's plan for the defence of Baltic countries unless the alliance recognises a Kurdish  group as "terrorists", Turkish President Recep Tayyip Erdogan warned.
A NATO meeting on Tuesday, marking the alliance's 70th anniversary, was set to be a tense affair with Turkey at odds with other members over its purchase of Russian missiles and recent offensive in northern Syria, among other issues.
Speaking at a news conference in the capital, Ankara, before his departure for the British capital, Erdogan urged unconditional support of the alliance in the fight against the Kurdish People's Protection Unit (YPG), which Turkey views as a terrorist organisation.
"NATO needs to act in a proactive manner against threats posed by the terrorist organisations," Erdogan said. "It is inevitable that NATO is in need of readjusting itself against today's terrorist threats. We expect our allies to display strong cooperation with us against the threats we are facing."
Relations between Turkey and its NATO allies have been strained over a host of issues, ranging from Ankara's decision to procure Russian air defence systems to its policy on Syria.
Several NATO members also condemned Turkey's decision to launch an offensive into northeastern Syria against the YPG group.
Erdogan said he had spoken to Polish President Andrzej Duda on the phone on Monday and agreed to discuss the military operation with Poland and the Baltic countries in London.
"With pleasure, we can come together and discuss these issues there as well," he said. "But if our friends at NATO do not recognise as terrorist organisations those we consider terrorist organisations ... we will stand against any step that will be taken there."
The security alliance has come under criticism recently with French President Emmanuel Macron calling it "brain dead" owing to the lack of strategic cooperation among members.
Erdogan fired back at Macron over his criticism of Turkey's military operation in northeast Syria, saying he was suffering "brain death".
US President Donald Trump said on Tuesday Macron had been "very insulting".
"It's a tough statement, though, when you make a statement like that, that is a very, very nasty statement to essentially 28, including them, 28 countries," Trump told reporters as he met the head of NATO, Jens Stoltenberg.
Al Jazeera's Jonah Hull, reporting from London, said there was a "potential for spats" at the short summit.(FA)