Tim McCormack, programme coordinator of the Asian Turtle Programme, said photos taken of it in a holding tank showed injuries on its legs and elsewhere, but it was not yet clear how serious they are. The animal is believed to be about 80 to 100 years old, which could mean it will require longer treatment. However, many Vietnamese believe it is the same mythical creature said to have helped King Le Loi fend off the Chinese nearly six centuries ago.

Veterinarians on Monday examined a giant turtle considered sacred by many Vietnamese to try to determine how to treat its wounds, a day after it was captured in a central Hanoi lake.

Tests were being run to try to pinpoint what’s ailing the creature that has a shell the size of a desk, said Tim McCormack, programme coordinator of the Asian Turtle Programme. Only four of the freshwater species are believed to be living worldwide.

He said photos taken of it in a holding tank showed injuries on its legs and elsewhere, but it was not yet clear how serious they are. The animal is believed to be about 80 to 100 years old, which could mean it will require longer treatment. However, many Vietnamese believe it is the same mythical creature said to have helped King Le Loi fend off the Chinese nearly six centuries ago.

It took 50 workers two hours on Sunday to net the turtle, put it in a cage and pull it to a small island in Hoan Kiem Lake that was recently expanded and equipped with the small holding tank, known as the “turtle hospital.”

It is the first time anyone has captured the creature, which escaped through two nets during a similar rescue attempt last month. Thousands of onlookers crammed around the lake for a glimpse, which is considered lucky. The crowd whooped and clapped when the turtle was finally captured, but they were pushed back when it was taken to the island. A guard is now posted near the site, allowing entry only to accredited officials.

Concerns had mounted after the turtle was recently spotted with lesions on its head and shell, prompting the government to form committees and employ hundreds of workers to frantically clean debris and pollution from the lake.

The reptile is estimated to weigh about 440 pounds (200 kilograms) and is one of the world’s most endangered freshwater turtles. There is one other turtle of the same species, known as Rafeteus swinhoei, in Vietnam and two others in a Chinese zoo. But its value to the nation has nothing to do with how rare it is.

Legend has it that it is the same mythical creature said to have helped Vietnamese King Le Loi fend off the Chinese nearly six centuries ago.

After the victory, the king was said to be boating on the lake when a giant golden turtle rose to the surface and snatched the sword with its mouth before plunging deep into the water to return it to its divine owners.

Hoan Kiem Lake, which serves as the capital’s center-piece, translates as “Lake of the Returned Sword.”