WASHINGTON (AP) - Condolences are pouring in from around the world to the National Zoo in Washington, a day after the death of a 6-day-old panda cub.

Zoo officials say the cub had liver abnormalities, but a cause of death won't be known until further tests are complete.

They say the cub appeared to be in good condition. It had been drinking its mother's milk. And it wasn't accidentally crushed to death by its mother, which has happened to other panda cubs in captivity.

The mother panda has started eating and interacting with her keepers again. She slept last night while cradling a plastic toy, in what zoo officials say was an apparent show of maternal instinct.

One Virginia woman who brought her two young sons to see the pandas today says she feels sorry for the mother -- who she says must be "in mourning."

Zoo director Dennis Kelly says, "Every loss is hard" -- but that this one is "especially devastating." He says workers had put in a lot of work over the past six years, in the hopes of producing another cub.

Zoo officials aren't ruling out another effort to impregnate the mother panda -- who, at the age of 14, may still have a few years of fertility.

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