U.S. Secretary of State Mike Pompeo arrived in Tokyo on Saturday for talks with Prime Minister Shinzo Abe and other officials ahead of his fourth visit to North Korea for denuclearization talks with its leader Kim Jong Un.

Despite Kim’s pledge to denuclearize the Korean peninsula, Japan, Washington’s key ally in Asia, still considers North Korea to be a “dire threat,” and is pushing ahead with plans to bolster its ballistic missile defenses with Aegis Ashore batteries that can target warheads in space.

Speaking to a pool reporter en route to Tokyo, Pompeo said his aim in Pyongyang was “to make sure we understand what each side is truly trying to achieve.” He also said he hoped to be able to agree a “general date and location” for a second summit between U.S. President Donald Trump and Kim Jong Un following their first meeting in Singapore in June.

Pompeo’s last visit to North Korea failed to make progress with Pyongyang denouncing him for making “gangster-like demands.”

Recently, he angered North Korea by insisting that international sanctions must remain in place until it gives up its nuclear weapons. On Wednesday, he said there was unanimous support for this at last week’s U.N. General Assembly, even if Russia and China “had some ideas about how we might begin to think about a time when it would be appropriate to reduce them.”