Vice Foreign Minister Shinsuke Sugiyama will succeed Kenichiro Sasae as Japan's ambassador to the United States, government sources said Saturday.

Sugiyama, 64, is well-versed in international law, having held such posts as chief of the Treaties Division and head of the Asian and Oceanian Affairs Bureau before assuming his current post in June 2016.

The Prime Minister's Office and the ministry have been looking for a successor to Sasae, 66, because he has held the post for over five years, the sources said.

Sasae became Japan's ambassador to the United States in September 2012 after serving as vice foreign minister.

Sugiyama is expected to maintain good communications with key personnel in the administration of President Donald Trump, as Prime Minister Shinzo Abe places importance on strengthening the U.S.-Japan alliance, the sources said.

Sasae is said to have built solid relations with Jared Kushner, Trump's senior adviser and son-in-law, bolstering ties between the two leaders.

Senior Deputy Foreign Minister Takeo Akiba is a strong candidate to succeed Sugiyama as the ministry's top bureaucrat, the sources said.