China's Foreign Ministry confirmed Tuesday that Japanese authorities have detained a Chinese fishing boat for alleged illegal fishing.

Ministry spokeswoman Jiang Yu gave no details of the vessel or its crew, but she urged Japanese authorities to ensure the crew members' legal rights.

Jiang told a regular press conference that the Japanese fisheries department had informed China's Consulate-General in Osaka that the boat was detained for "fishing across the border."

The ministry gave no details on when the boat was detained and how many crew members were in custody.

Jiang said the Chinese authorities were investigating the case.