A senior U.S. state department official overseeing East Asia and the Pacific expressed deep concerns regarding Russian President Vladimir Putin's recent visit to North Korea and the close military cooperation between the two sides.

During a U.S. House subcommittee hearing on Thursday, U.S. Assistant Secretary of State for East Asian and Pacific Affairs Daniel Kritenbrink characterized Putin's visit as the latest manifestation of the two sides' "deeply disturbing and growing partnership."

Although he stressed that America will always keep the door to dialogue open, the official said that, given the current circumstances, there is no choice but to double down on U.S. deterrent capabilities.

Kritenbrink also underscored the need to strengthen bilateral and trilateral cooperation among South Korea, the U.S. and Japan, and work with the international community to increase sanctions aimed at deterring North Korea and its partnership with Russia.
 
When asked about his stance on a bill introduced by Democrat Congressman Brad Sherman proposing an agreement for a formal end to the Korean War, Kritenbrink said he believes "everything should be on the table" as long as there were regular dialogue channels with Pyongyang for progress on denuclearization.