Two Russian nationals were sentenced to 15 months' jail on Wednesday for smuggling 206 turtles through Singapore.

Both men, Pavlychev Maksim, 38, and Radkov Aleksei, 34, were detained at Changi Airport on July 9 after security officers found their four luggage bags stuffed with live turtles. They had planned to deliver the turtles to Surabaya through Singapore after a friend approached them to do so.

The bags, which had arrived on a flight from Dhaka, were lined with diapers and cloth to absorb the turtles' waste, said a spokesman for the Agri-Food and Veterinary Authority on Wednesday.

The black pond turtles, a critically endangered species banned from international trade, had arrived in Singapore dehydrated, he added.

The 206 turtles are estimated to be worth $90,000.

So far, 27 turtles have died or had to be put down.

Under the Endangered Species (Import and Export) Act, permits from the Convention on International Trade in Endangered Species of Wild Fauna and Flora (Cites) are required to import, export or re-export any of its protected species, including their parts and products.

It is an offence if Cites species or their parts and products do not have the necessary permits when they are in transit or being shipped through Singapore.

Penalties for infringing the Act include fines of up to $50,000 per species, capped at $500,000, and/or up to two years' jail.

Under the Animals and Birds Act, anyone who neglects to supply the animals with food and/or water or subjects them to unnecessary suffering and distress is guilty of animal cruelty.

Those convicted can be fined up to $10,000 and/or jailed up to 12 months.