The prime minister of Laos, Thongsing Thammavong, arrived in Tokyo on Wednesday for a four-day official visit to commemorate the 60th anniversary of diplomatic relations with Japan and expand political and economic ties between the two countries.

Thongsing plans to hold an audience with Emperor Akihito and a meeting with Prime Minister Shinzo Abe on Friday, according to the Foreign Ministry.

The visit comes as the two countries step up economic ties, with the number of Japanese investors in Laos doubling to about 120 late last year from the 2012 level, according to Japanese government data.