BEIJING (REUTERS) - China on Thursday expressed "serious concern" over the blowing up of a Chinese fishing vessel seized by Indonesia six years ago, the first such incident under President Joko Widodo.

The Chinese Foreign Ministry said the country had pressed Indonesia for more details about the destruction of the Chinese boat, which was among 41 vessels suspected of illegal fishing that were blown up by Indonesia on Wednesday. Other countries with boats destroyed include Thailand and Vietnam.

Since taking office last October, Mr Widodo's administration has blown up dozens of foreign vessels as part of his get-tough campaign against illegal fishing.

But no Chinese vessels were destroyed prior to this week due to delays from legal challenges, an Indonesian government official said.

The Chinese boat was seized by Indonesia in 2009. It was not immediately clear what had happened to the crew when it was seized.

The blowing up of the boats comes amid increased tension in the nearby South China Sea over overlapping territorial claims among China, the Philippines, Vietnam, Malaysia, Brunei and Taiwan. Indonesia is not involved.

Chinese fishing boats have also been illegally fishing in large numbers off West Africa, Greenpeace said on Wednesday, adding that Chinese companies expanded operations in Africa from 13 vessels in 1985 to 462 vessels in 2013.