China on Thursday said Japan's concerns over China's exploitation of gas fields in the East China Sea were "unnecessary".

Chinese Foreign Ministry spokeswoman Jiang Yu said China's oil and gas exploitation activities were legitimate.

It was reported on Wednesday that a Japanese official expressed concern over exploitation activities at a Chinese drilling platform in the East China Sea's Pinghu gas field.

"We believe the concerns and misgivings expressed by Japan are unnecessary," Jiang said.

Source: Xinhua