U.S. Ambassador to Japan William Hagerty said Friday that President Donald Trump's first visit to Tokyo earlier this month was a big success, especially in terms of advancing discussions on "unfair" trade relationships between the two countries.

"During his successful visit to Japan, the president strengthened his close relationship with Prime Minister (Shinzo) Abe, and moved the relationship forward on both security and trade issues," Hagerty, who became ambassador in July, said during a news conference at the Japan National Press Club in Tokyo.

"The president and Prime Minister Abe had significant discussions regarding trade," he said.