Turkey’s president Tuesday afternoon gathered with the leaders of France, Germany, and the U.K. in London ahead of a NATO summit.

Recep Tayyip Erdogan’s meeting with his counterparts started at around 3 pm (1500GMT) local time and is expected to last slightly over an hour.

French President Emmanuel Macron and German Chancellor Angela Merkel, both in London for the NATO summit, alongside host British Prime Minister Boris Johnson, met Erdogan at 10 Downing Street, the prime ministerial residence.

“Developments regarding our Operation Peace Spring will be evaluated,” Erdogan said earlier, referring to Turkey’s anti-terrorist operation in northern Syria launched

Read more: Erdogan meets UK, French, German leaders