Earlier Erdogan had rattled preparations for NATO's Vilnius meeting by declaring that he would only back Sweden's candidacy for the Western alliance if European Union members -- most of whom are also NATO allies -- agree to revive Turkey's negotiations to join the EU.

The Turkish leader held talks with NATO Secretary General Jens Stoltenberg and Swedish Premier Ulf Kristersson in Vilnius in a push to get Ankara to lift its year-long block on Stockholm.

Diplomats said that meeting was then put on hold while Erdogan sat down with European Council head Michel.

It was unclear what Michel, who heads the body representing the EU's 27 leaders, could offer to Erdogan to help break the deadlock.

German Chancellor Olaf Scholz, an EU and NATO heavyweight, has insisted there is no link between Stockholm's quest to join the Western military alliance and Ankara's long-stalled application to enter the EU.