Outgoing US Ambassador to Japan Rahm Emanuel has said that he believes the US-Japan alliance was improved during his time in office.

Emanuel made the remarks at a news conference in Tokyo on Friday. He is due to vacate his post later this month with President Joe Biden's departure from office.

Looking back on his three-year term, Emanuel said he can say "with some confidence that the US-Japan alliance is better prepared than it was before."

He referred to efforts to improve the command and control of Japan's Self-Defense Forces and the US military through reorganization of command functions.

Emanuel said, "Both security apparatuses are changing the security architectural foundations of the alliance to better collaborate and better coordinate."

He also mentioned the trilateral framework of Japan, the US and South Korea and that of Japan, the US and the Philippines, that he worked to strengthen while in office.

The ambassador stressed the importance of further enhancing cooperation between allies to counter threats posed by China and Russia.

When asked about his view about where incoming US President Donald Trump is going to take the country, he declined to answer directly.

About US President Joe Biden's order blocking the planned buyout of U.S. Steel by Japanese firm Nippon Steel, he said he thinks the Japan-US alliance is "deeper and stronger than any single one economic transaction or business transaction."