Japan's Prime Minister Yoshihiko Noda says China must take steps to prevent violence against Japanese citizens.
Anti-Japanese protests have spread to cities across China in an escalating row over disputed islands in the East China Sea.
Hundreds of protesters faced off against riot police at the Japanese embassy in Beijing on Sunday and Japanese businesses have also been targeted by protesters.
Mr Noda has told Japanese television that Japan wants China to oversee the situation so Japanese citizens and businesses in China will not be in danger.
The BBC reports tensions have been heightened this week after the purchase of some of the islands by the Japanese government from their private Japanese owners.