"They (i.e. Turkey) are simultaneously carrying out large-scale arms procurement from Russia, so there is no question about their credibility. The NATO summit, which also marks the organization's 70th anniversary, could lead to the question of Turkey's membership in NATO," Madison stated on his social media page, news portal Delfi reports (link in Estonian).

Erdogan said ahead of the NATO London summit on Tuesday and Wednesday that he would not support the Polish-Baltic States defense plan until NATO in turn supported Ankara over its concerns over the fight against Kurdish YPG forces in northern Syria, which it views as a terrorist organization.

In summer, Turkey, a NATO member since 1952, met widespread criticism for taking delivery of state-of-the-art air defense systems from the Russian Federation.

Article 3 of the North Atlantic or NATO Agreement states: "In order to further the objectives of the Agreement, the Parties shall individually and jointly, continuously and effectively develop and assist each other in their individual and collective capacity to withstand an armed attack."

Madison said that since Article 3 of the NATO treaty says that member states should jointly, continuously and effectively develop and assist each other in their capacity to withstand armed attack, both individually and collectively, Erdogan is in direct violation of the treaty, as well as guilty of blackmailing other member states.

"If Turkey intentionally seeks to undermine the collective ability to resist an armed attack and refuse to help one another, I am not very sure that continuing Turkey in NATO is still in our common interest," Madison wrote.

Estonian foreign minister Urmas Reinsalu said a meeting between Turkey's leadership and that of the Baltic States and Poland was to take place on the issue, at the London summit.

MEP Urmas Paet (Reform), who had also hit out at Turkey's arms deal with Russia, said that Erdogan has already ruined Turkey's relations with the EU and its member states, and is now attempting to do the same with members of NATO.

Former Estonian Defence Forces (EDF) Commander and Reform MP Ants Laaneots last week also referred to Turkey's stance as one of blackmail.

The summit follows remarks from French President Emmanuel Macron that NATO was "brain dead" following the pulling-out of U.S. troops from northern Syria in mid-October. However, media reports say that the U.S. has been reengaging in counter-terrorism missions in northern Syria.

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