HANOI, Vietnam >> Thousands of Vietnamese jostled and climbed trees around a lake in the capital Tuesday hoping to see a rare giant turtle considered sacred by many but in desperate need of medical attention.

Dozens of workers waded chest-deep through the chilly green water in Hanoi’s Hoan Kiem Lake to try to capture the giant freshwater creature for the first time, so it could be pulled to an island and treated. It is one of the world’s most endangered turtles — one of only four Rafeteus swinhoei believed to be alive today — but its value to the nation transcends the natural world.

The turtle traces its roots back through hundreds of years of local folklore, and some even believe the animal that lives in the lake today is the same mythical creature said to have helped a Vietnamese king fend off the Chinese nearly six centuries ago.

In recent days, photos of it surfacing with open pink sores on its wrinkled neck and legs have sparked near panic among the public, with newspapers carrying front-page stories and Internet chatrooms buzzing with opinions. Lesions were also visible on its shell, which stretches 6 feet long (1.8 meters long) and 4 feet wide (1.2 meters wide).

Some experts fear the water in the sewage-filled and trash-strewn lake is slowly killing the turtle, which is thought to weigh about 440 pounds (200 kilograms) and is affectionally called "great-grandfather." Hundreds of Vietnamese have been working around the clock removing chunks of debris from the lake and pumping in fresh water.

Last week, a small island in the lake was expanded with sandbags to form a platform large enough for the turtle to rest, complete with a little pond. Rescuers were hoping to coax it ashore, but, when it did not emerge on its own, dozens of men carrying a large net waded into the water Tuesday to ring it and drag it to the island.

But even with the military involved in the rescue, the turtle managed to slip through the nets and escape, ending Tuesday’s efforts. Officials planned to meet to decide the next steps.

"I’m really glad that I’m part of the rescue operation and, hopefully, it will bring luck to my family," said Nguyen Thanh Liem, 65, a retired army captain who had helped pull the net along. "I wish that he would be immortal to bless our nation."

Liem, like many Vietnamese, believes the turtle is the same one described in the legend of King Le Loi, who is said to have defeated Chinese invaders with a magic sword given to him by the gods. 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 in its mouth before plunging deep into the water to return it to its divine owners.

Experts, however, say the Hoan Kiem turtle is more likely 80 to 100 years old. Only three others of its kind are known to be alive: one in another lake in Vietnam and two in a Chinese zoo.

Some gathered at Hoan Kiem Lake, which translates as "Lake of the Returned Sword," worried that trying to wrangle the creature could do more harm than good.

"It’s not safe to use the net to try to catch the turtle. It could worsen his wounds," said Nguyen Hung Cuong, a 19-year-old student.