Mattis said after his meeting with Japanese Defense Minister Tomomi Inada on Saturday the new US administration under Donald Trump places a high priority on the Asia-Pacific region, and "specifically on long-term allies like Japan.
"Mattis's remarks have been considered by some Japanese media as aiming to ease concerns from the Japanese side, as certain remarks by the US President Donald Trump about Japanese currency valuations and the cost the US incurs in posting its troops to Japan have perplexed the government here.
During the election campaign, Trump has been quoted by media as saying that he might withdraw US forces from Japan if Tokyo did not shoulder the entire cost burden.
Inada said the issue did not come up in her meeting with Mattis, while Mattis, for his part, said that Japan is a "model" regarding cost-sharing with the United States.
He also noted Japan's growing defense budget since Prime Minister Shinzo Abe took office in 2012, saying that it was "on the right track."
Regarding the controversial Futenma relocation plan, the two defense chiefs agreed that the plan to move US Marine Corps Air Station Futenma to less-populated Henoko area within the prefecture is the only solution, though the plan has been strongly opposed by the Okinawa people.
"If (the US and Japanese governments) stick to the view that Henoko is the only solution to resolve (issues involving the Futenma base), it will leave serious problems in the future," said Okinawa Governor Takeshi Onaga on Friday.
Mattis, on his first trip to Japan since taking over the Pentagon, on Friday met with Japanese Prime Minister Shinzo Abe and Foreign Minister Fumio Kishida.
According to a statement by Japan's foreign ministry, Mattis said in his meeting with Abe that the disputed Diaoyu islands fall under Article 5 of the US-Japan mutual defense treaty.
The clause commits the United States to defend territories that are under the administrative control of Japan.
China on Friday urged the United States to stop making wrong remarks on the issue of the Diaoyu Islands sovereignty. "The Diaoyu Island and its adjacent islets have been an inherent part of Chinese territory since ancient times, which is a unchangeable historical fact," Chinese Foreign Ministry spokesman Lu Kang said.
Lu said the so-called US-Japan treaty of mutual cooperation and defense is a product of the Cold War, which should not impair China's territorial sovereignty and legitimate rights."We urge the US side to take a responsible attitude, stop making wrong remarks on the issue involving the Diaoyu Islands sovereignty, and avoid making the issue more complicated and bringing instability to the regional situation," said the spokesman.
XINHUA/MNA