Secretary of State Mike Pompeo welcomed Foreign Minister Taro Kono for talks ahead of a planned expanded session with the two allies' defense chiefs.

The meeting comes nearly two months after President Donald Trump walked away from a summit in Hanoi with North Korean leader Kim Jong Un as the United States presses for the authoritarian state to eliminate its nuclear program.

With no visible progress since then, North Korea this week demanded that Pompeo be excluded from future negotiations after he apparently encouraged Trump to stand firm.

The regular "two-plus-two" dialogue is one of a flurry of meetings between the allies, with Japanese Prime Minister Shinzo Abe due in Washington next week.

Trump and his wife Melania will then travel to Japan in May as the first state guests following the enthronement of Naruhito as emperor.

Japan has publicly backed Trump's drive to make peace with North Korea but has been cautious on chances for success.

Abe built his political career demanding tough action against North Korea over its abductions of Japanese citizens in the 1970s and 1980s to train its spies.