Beijing, Feb 4 (IANS): China has urged the US to stop making erroneous remarks on the sovereignty of the Diaoyu Islands after American Defence Secretary James Mattis reportedly said the US-Japan mutual defence treaty applies to the disputed islands in the East China Sea.

"The Diaoyu Island and its adjacent islets have been an inherent part of Chinese territory since ancient times, which is a unchangeable historical fact," Foreign Ministry spokesman Lu Kang said late Friday.

The remarks comes after Mattis, upon his arrival in Tokyo earlier on Friday, reaffirmed Washington's commitment to defending Japanese territory in the region.

Lu said the so-called US-Japan treaty of mutual cooperation and defence is a product of the Cold War, which should not impair China's territorial sovereignty and legitimate rights, the Global Times reported.

"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.

Beijing and Tokyo are involved in sovereignty disputes over the Diaoyu Islands, known as Senkaku in Japan.

The sovereignty dispute over the Senkaku Islands, administered by Tokyo, has intensified since Japan nationalised three islets in 2012, Efe news said.

The uninhabited archipelago occupies some 7 sq.km and the surrounding waters are believed to hold significant reserves of oil and gas.