BEIJING -- Chinese Vice Foreign Minister Cheng Guoping on Thursday expressed strong dissatisfaction with Russia over an alleged attack on a Chinese fishing vessel, which has left a fisherman missing.

China is very dissatisfied with Russia's actions to detain the Chinese fishing boat and crew after opening fire on the boat, Cheng said in a statement when summoning a Russian diplomat.

China demands Russia to thoroughly investigate the incident and inform China of the results in a timely manner, Cheng said.

Russia should make sure that the detained sailors are safe, their legitimate rights are guaranteed and they are granted with humanitarian treatment, Cheng said.

Earlier media reports said Russia also detained another Chinese fishing boat one day before the attack which occurred on Monday.

Cheng also demanded Russia to release the boats and let the fishermen go quickly and make all-out efforts to search for the missing sailor.

The Russian diplomat said Russia is investigating the incident, and will notify China as early as possible. He said he will report China's stance back to Russia.