China urges Japan to protect the lawful rights and interests of the recently detained Chinese sailors and to resolve the issue properly as soon as possible, a Foreign Ministry spokesman said Tuesday.

Hong Lei, the spokesman, said at a daily press briefing that China has noticed the relevant reports and the issue is under investigation.

"It is an ordinary fishing boat issue," Hong said. "China urges Japan to resolve the matter as soon as possible."

According to a foreign media report, a Japanese coastguard patrol boat spotted two Chinese fishing boats Sunday, close to the islands off Japan's southwest coast.

The 47-year-old captain of one of the fishing boats was arrested and detained along with 10 crew members.