U.S. President Joe Biden speaks with Britain's Prime Minister Boris Johnson during a plenary session at a NATO summit in Brussels, Belgium, June 14, 2021. Olivier Matthys/Pool via REUTERS
NATO Secretary General Jens Stoltenberg welcomes North Macedonia's Prime Minister Zoran Zaev during the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Kenzo Tribouillard/Pool via REUTERS
France's President Emmanuel Macron talks with Bulgaria's President Rumen Radev during the NATO summit at the Alliance's headquarters, in Brussels, Belgium June 14, 2021.
Estonia's Prime Minister Kaja Kallas speaks to the media upon her arrival for the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Kenzo Tribouillard/Pool via REUTERS
Turkey's President Tayyip Erdogan fist bumps U.S. President Joe Biden during a plenary session at a NATO summit in Brussels, Belgium, June 14, 2021. Olivier Matthys/Pool via REUTERS.
Turkey's President Tayyip Erdogan and Germany's Chancellor Angela Merkel pose with other NATO Heads of the states and governments for a family photo during the NATO summit at the Alliance's headquarters, in Brussels, Belgium June 14, 2021.
German Chancellor Angela Merkel arrives to pose for photos with NATO Secretary General Jens Stoltenberg during the NATO summit at NATO headquarters in Brussels, Belgium, June 14, 2021. Patrick Semansky/Pool via REUTERS
NATO Secretary General Jens Stoltenberg holds a news conference ahead of the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Francisco Seco/Pool via REUTERS
Slovakia's President Zuzana Caputova arrives for the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Kenzo Tribouillard/Pool via REUTERS
U.S. President Joe Biden, Spain's Prime Minister Pedro Sanchez and Canada's Prime Minister Justin Trudeau speak during the NATO summit at the Alliance's headquarters, in Brussels, Belgium June 14, 2021.
France's President Emmanuel Macron talks with U.S. President Joe Biden, near Britain's Prime Minister Boris Johnson before a plenary session at a NATO summit in Brussels, Belgium, June 14, 2021. Brendan Smialowski/Pool via REUTERS
NATO heads of the states and governments look at a digital installation after posing for a family photo, during the NATO summit at the Alliance's headquarters in Brussels, Belgium June 14, 2021.
NATO Secretary General Jens Stoltenberg welcomes Denmark's Prime Minister Mette Frederiksen during the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Kenzo Tribouillard/Pool via REUTERS
NATO Secretary General Jens Stoltenberg welcomes Denmark's Prime Minister Mette Frederiksen during the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Francois Mori/Pool via REUTERS
NATO Heads of the states and governments pose for a family photo during the NATO summit at the Alliance's headquarters, in Brussels, Belgium June 14, 2021.
U.S. President Joe Biden attends a plenary session at a NATO summit in Brussels, Belgium, June 14, 2021. Brendan Smialowski/Pool via REUTERS
German Chancellor Angela Merkel arrives for a NATO summit in Brussels, Belgium, June 14, 2021. Kenzo Tribouillard/Pool via REUTERS
Turkey's President Tayyip Erdogan, U.S. President Joe Biden and NATO Secretary General Jens Stoltenberg talk as Britain's Prime Minister Boris Johnson sits before a plenary session at a NATO summit in Brussels, Belgium, June 14, 2021. Brendan Smialowski/Pool via REUTERS
Belgium's Prime Minister Alexander De Croo and Belgium's Foreign Minister Sophie Wilmes arrive for the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Kenzo Tribouillard/Pool via REUTERS
NATO Secretary General Jens Stoltenberg welcomes U.S. President Joe Biden during the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Patrick Semansky/Pool via REUTERS
Norway's Prime Minister Erna Solberg arrives for the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Kenzo Tribouillard/Pool via REUTERS
NATO Secretary General Jens Stoltenberg welcomes Norway's Prime Minister Erna Solberg during the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Kenzo Tribouillard/Pool via REUTERS
Germany's Chancellor Angela Merkel and Turkey's President Tayyip Erdogan pose for a family photo with other NATO Heads of the states and governments during the NATO summit at the Alliance's headquarters, in Brussels, Belgium June 14, 2021.
U.S. President Joe Biden and NATO Secretary-General Jens Stoltenberg greet each other after the NATO summit in Brussels, Belgium June 14, 2021.
France's President Emmanuel Macron talks with U.S. President Joe Biden before a plenary session at a NATO summit in Brussels, Belgium, June 14, 2021. Brendan Smialowski/Pool via REUTERS
NATO Secretary General Jens Stoltenberg greets France's President Emmanuel Macron during the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Patrick Semansky/Pool via REUTERS
Turkey's President Tayyip Erdogan holds a news conference during the NATO summit at the Alliance's headquarters in Brussels, Belgium June 14, 2021.
U.S. President Joe Biden attends a bilateral meeting with Turkey's President Tayyip Erdogan (not pictured) on the sidelines of the NATO summit in Brussels, Belgium June 14, 2021.
Britain's Prime Minister Boris Johnson arrives for the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Kenzo Tribouillard/Pool via REUTERS
Human rights acrivists take part in a protest demanding the closure of the U.S. prison at Guantanamo, during the NATO summit in Brussels, Belgium June 14, 2021.
Britain's Prime Minister Boris Johnson arrives for posing with NATO Secretary General Jens Stoltenberg during the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Kenzo Tribouillard/Pool via REUTERS
U.S. President Joe Biden attends a meeting with NATO Secretary General Jens Stoltenberg during a NATO summit, at the Alliance's headquarters in Brussels, Belgium, June 14, 2021. Stephanie Lecocq/Pool via REUTERS
U.S. President Joe Biden arrives to pose with NATO Secretary General Jens Stoltenberg (not pictured) during the NATO summit at the Alliance's headquarters in Brussels, Belgium, June 14, 2021. Kenzo Tribouillard/Pool via REUTERS
NATO Secretary-General Jens Stoltenberg greets Turkey's President Tayyip Erdogan during the NATO summit at the Alliance's headquarters in Brussels, Belgium, June 14, 2021. Kenzo Tribouillard/Pool via REUTERS
U.S. President Joe Biden and NATO Secretary-General Jens Stoltenberg talk after the NATO summit in Brussels, Belgium June 14, 2021.
Britain's Prime Minister Boris Johnson arrives for the NATO summit at the Alliance's headquarters, in Brussels, Belgium, June 14, 2021. Olivier Hoslet/Pool via REUTERS
Inside the NATO summit