BEIJING - China on Thursday expressed serious concern over demonstrations by non-governmental groups in the Republic of Korea (ROK), urging the ROK to guarantee the safety of the Chinese embassy in Seoul and of other Chinese institutions in ROK.

"We have lodged complaints over demonstrations and radical behavior in front of the Chinese embassy in Seoul," Foreign Ministry spokesman Liu Weimin said during a regular press briefing.

According to Liu, the ROK said it respects China's concerns and regrets the aggressive behavior displayed outside the embassy.

The ROK promised to take further action to protect Chinese people and organizations in the country, Liu said.

Several groups and individuals have protested in front of the embassy this week after crew members on a Chinese fishing boat reportedly clashed with two ROK coast guards on Monday, leaving one coast guard dead and the other injured.