China has requested South Korea's cooperation in investigations into the death of 25 Chinese illegal immigrants.
Foreign Ministry spokesman Sun Yuxi said China want "active cooperation" and an "immediate and thorough investigation" into the incident.
The Chinese were suffocated in a storage tank and dumped into the sea by the crew of a South Korean ship in the Yellow Sea earlier this week.
The victims were among a group of 60 trying to get to South Korea to find work.
Thirty-five survivors, eleven of them ethnic Koreans, are in police custody and reportedly in good condition.
South Korean authorities plan to deport the survivors after receiving new travel documents from the Chinese embassy in Seoul.
Police in the southern port of Yosu are expected to issue arrest warrants for the South Korean captain and eight crew members on charges of involuntary homicide and abandoning bodies.
Maritime police are continuing the search for bodies.