The top diplomats of Japan, the United States and South Korea agreed Thursday to pursue closer cooperation in addressing North Korea's steady development of nuclear and missile capabilities, as well as its expanding military cooperation with Russia.

"Cooperation and coordination with our closest allies is more important than ever," U.S. Secretary of State Antony Blinken said as he met with his Japanese and South Korean counterparts, Yoko Kamikawa and Cho Tae-yul, in Rio de Janeiro, citing regional challenges also including "increasingly assertive actions" by China.

Blinken, Kamikawa and Cho also discussed efforts to maintain peace and stability across the Taiwan Strait and the ongoing Israel-Hamas war, according to the U.S. State Department's top spokesman, Matthew Miller.