Also discussed at the meeting were transatlantic cooperation, the situation in the Middle East as well as the EU's Eastern Partnership (EaP), according to a ministry press release.

Mikser thanked Johnson for the U.K.'s contribution to NATO's Enhanced Forward Presence (eFP) defense and deterrence posture in Eastern Europe, which helps ensure the security of the Baltic region.

"The U.K.'s role as leader of the NATO eFP battle group [in Estonia] has taken our security to a new level and significantly contributed to ensuring stability in the Baltic Sea region," Mikser said.

The Estonian minister emphasized that NATO must continue adapting and that transatlantic ties and the U.S. military presence in the Baltic region, along with increasing defense spending, remain important as well. "Cooperation between the EU and NATO is more important than ever before," he emphasized.

At the meeting, the nine foreign ministers also exchanged thoughts on developments in the UN Security Council, including the topic of North Korea.

Mikser also acknowledged the U.K.'s commitment to the EaP, thanking Johnson for organizing a high-level conference on reforms in Ukraine this past July.

NB8 participants at Monday's meeting, at Johnson's invitation, were Estonian Foreign Minister Sven Mikser, Finnish Foreign Minister Timo Soini, Swedish Foreign Minister Margot Wallström, Icelandic Foreign Minister Gudlaugur Thór Thórdarson, Norwegian Foreign Minister Børge Brende, Danish Foreign Minister Anders Samuelsen, Latvian Foreign Minister Edgars Rinkēvičs and Lithuanian Deputy Foreign Minister Darius Skusevicius.