JAKARTA, Indonesia - Researchers in a remote Indonesian jungle have discovered a tiny possum and a giant rat that is about five times the size of a typical city rat, scientists say.

Unearthing new species of mammals in the 21st century is considered rare. The discoveries by a team of American and Indonesian scientists, announced Monday, are being studied further to confirm their novelty.

The animals were found in the Foja mountains rain forest in eastern Papua province in a June expedition, said U.S.-based Conservation International, which organized the trip in the Southeast Asian nation along with the Indonesian Institute of Science.

"The giant rat is about five times the size of a typical city rat," said Kristofer Helgen, a scientist with the Smithsonian Institution in Washington. "With no fear of humans, it apparently came into the camp several times during the trip."

The possum was described as "one of the world's smallest marsupials."

A 2006 expedition to the same stretch of jungle - dubbed by Conservation International as a "Lost World" because until then humans had rarely visited it - unearthed scores of exotic new species of palms, butterflies and palms.

Papua has some of the world's largest tracts of rain forest, but like elsewhere in Indonesia, illegal logging is ravaging the land. Scientists said last year that the Foja area was not under immediate threat, largely because it was so remote.

"It's comforting to know that there is a place on Earth so isolated that it remains the absolute realm of wild nature," said expedition leader Bruce Beehler.