China said Tuesday it has looked into the case of a Chinese ship detained in Ecuador over charges of illegal fishing and that it does not tolerate any illegal trading of endangered wildlife.

An Ecuadorean judge has reportedly sentenced 20 Chinese crew members to up to four years in prison for illegal fishing off the Galapagos Islands and fined them a total of 5.9 million U.S. dollars.

The Chinese government opposes all forms of illegal fishing and exercises zero-tolerance toward actions that involve the illegal trading of endangered wildlife and their products, Foreign Ministry spokesperson Hua Chunying said at a regular news briefing.

"China will not side with any form of illegal fishing," she said.

Although there is no proof of fishing or transshipment by the ship in Ecuadorean waters, the ship did sail within the Galapagos marine reserve without permission, Hua said.

She said China will also investigate the ship's actions on the high seas and will punish all violations in line with both international and Chinese law.

China respects Ecuador's concerns over the Galapagos marine reserve, and will remind Chinese fishing vessels to comply with regulations and avoid entering the area, Hua said.

China hopes Ecuador will deal with the incident fairly and protect the rights of the Chinese crew, the spokesperson said.