China would firmly uphold its due rights in the East China Sea, a Foreign Ministry spokesman said Monday.

Spokesman Ma Chaoxu made the remarks while briefing the media on talks between Chinese Foreign Minister Yang Jiechi and his Japanese counterpart Katsuya Okada.

Yang has made clear China's stance on the East China Sea issue and stressed the sovereign rights of Chunxiao oil and gas field belong to China, Ma said.

According to the principled common understanding reached between the two countries on the East China Sea issue, the Japanese side could participate in the cooperative development of Chunxiao in accordance with relevant laws of China, but the cooperative development is different from "joint development."

Ma quoted Yang as saying the proper handling of the East China Sea issue was crucial for Sino-Japanese relations and regional stability.

Both sides agreed to keep contacts over the East China Sea issue, according to Ma.