U.S. Secretary of State Marco Rubio is wrapping his up his time at a Southeast Asian security conference with a meeting with his Chinese counterpart as tensions grow over issues from trade to security and China’s support for Russia’s war in Ukraine.

Secretary of State Marco Rubio met with Russian Foreign Minister Sergey Lavrov in Malaysia Thursday at a meeting of the Association of Southeast Asian Nations. The meeting put the Russia-Ukraine war at the center of a trip that was meant to strengthen alliances in Southeast Asia.

Rubio said the U.S. tariffs imposed on many Asian countries, including the heaviest levies on China, were a top complaint at the summit.