Tokyo, Feb 4 (IANS): US Defence Secretary James Mattis on Saturday reaffirmed Washington's commitment to defending Japan, including a group of disputed islands which have been claimed by China.

"I made clear that our long-standing policy on the Senkaku Islands stands -- the US will continue to recognise Japanese administration of the islands and as such Article 5 of the US-Japan Security Treaty applies," Mattis said in a press conference with Japanese Defence Minister Tomomi Inada, CNN reported.

Article 5 of that treaty says the US will defend territories under Japanese administration, which would include the Senkakus, an uninhabited group of islands in the East China Sea called the Diaoyus by China.

Tensions have flashed numerous times in recent years over the islands, including face-offs between Japanese and Chinese air and naval forces that have been termed dangerous by both sides.

Mattis' visit to Japan and South Korea follows a campaign in which President Donald Trump unsettled the region by suggesting that Seoul and Tokyo develop their own nuclear weapons and pay more towards keeping US troops stationed in the two countries.

But in his inaugural trip as Secretary of Defence, Mattis has repeatedly reassured the staunch US allies of the Trump administration's commitment to the region.

"I want there to be no misunderstanding during the transition in Washington that we stand firmly, 100 per cent shoulder to shoulder with you and the Japanese people," Mattis said.