Chinese state media say border patrol officials have seized 620 wild turtles and tortoises — 510 of them considered endangered — that were found alive in a shipment of frozen seafood from Vietnam.

The official Xinhua News Agency said Sunday that border police detected crawling sounds when they were inspecting the shipment at a border city in the southwestern region of Guangxi on Aug. 24.

Xinhua said police discovered the endangered species, including Indochinese box turtles and elongated tortoises, in a shipment heading for the neighboring province of Guangdong, where the animals are considered delicacies.

The local state-run Nanning Evening News says border officials grew suspicious when the cargo was clearly more than what had been declared and that the driver was nervous when interrogated.