BANDUNG (AFP/Reuters) - A critically endangered Sumatran elephant has become the latest animal to die in one of Indonesia's ill-maintained zoos, an official said on Thursday (May 12), sparking anger from activists and politicians.

The female elephant, called Yani, died in the city of Bandung on Java island Wednesday after falling ill a week earlier.

Many of the country's zoos are in poor condition and house animals in filthy, cramped enclosures. The most notorious, in the city of Surabaya, has been dubbed the "death zoo" as hundreds of animals have perished there.

Bandung zoo said the cause of Yani's death was yet to be determined, but the creature appeared lethargic before she died and pictures showed large sores on her body.

Efforts to save the elephant were hampered as the zoo had been without a resident veterinarian for almost a year, zoo spokesman Sudaryo admitted.

But the spokesman, who like many Indonesians goes by one name, insisted the zoo had done all it could by consulting an outside vet and elephant-keeper and providing medicines.

Bandung mayor Ridwan Kamil visited the sick elephant before it died, as anger mounted about the case, and urged the privately-run zoo to seek outside help.

"If they don't have the budget to manage (the zoo), they should seek support," he said.

An online petition calling for the zoo to be cleaned up, which has gathered over 10,000 signatures, said animals there looked emaciated and cages were dirty and rusty.

The zoo has reportedly been temporarily closed as the elephant's death is investigated, according to local media.

Animal activist Femke den Haas, from rights group the Jakarta Animal Aid Network, criticised a lack of clear rules about how Indonesian zoos should be run with regard to such things as cage size and feed.

"Yani's case is really just the tip of the iceberg because many animals are dying in Indonesian zoos," she said.

Over in Surabaya, so many animals have perished at Indonesia's biggest zoo that wildlife activists call it the "zoo of death" and are demanding an overhaul of its management.

Activists say many of the more than 2,200 animals at the zoo in the city of Surabaya are crowded into cages and enclosures far too small for them, and they also face a shortage of proper feed.

One of the latest losses was a rare Sumatran tiger that died unexpectedly last month.

"They need to make an effort to ease the overpopulation of animals," Mr Petrus Riski of the Indonesia Wildlife Communication Forum said at the zoo as keepers carried a crate of fish into a congested pen of pelicans.

"It can be done by sending them to other conservation institutes."

Zoo keepers attribute most of the deaths to natural causes, and said the tiger's death was still unexplained. But activists point to a string of unusual incidents that undermine their confidence in the zoo, which was founded in 1916.

An 18-month African lion was found hanging dead in its cage in 2014 and a dead giraffe was found with about 18kg of plastic in its stomach - rubbish thrown into its cage by visitors.

About 45 Komodo dragons, a large species of lizards only found in eastern Indonesia, died in battles they fought against each other in their overcrowded cage.

The zoo's director blamed bureaucratic hurdles hampering efforts to improve conditions.

"We've been trying to resolve these issues one by one," said director Aschta Boestani Tajudin. "I hope in three to four months from now we can finally solve the problem."

But critics are not convinced. They say poor staff training and outdated facilities are to blame for the zoo's woeful record. "They need more support and funds to really fix things,"said Mr Tony Sumampau, secretary general of the Indonesian zoo and aquarium association.

The WWF estimates there are between 2,400 to 2,800 Sumatran elephants left in the wild, with poaching and loss of their rainforest habitat blamed for population decline.

They are classified as critically endangered by the International Union for Conservation of Nature.