Updated

Myanmar's pro-democracy leader Aung San Suu Kyi was taken to a hospital Friday with a stomach ailment but her condition has improved and she has returned home, a spokesman for her party said Saturday.

Nyan Win of the National League for Democracy party said that Suu Kyi was taken to hospital on Friday but was returned home after her condition improved.

Anti-government activists in the United States, citing contacts from inside Myanmar, had said Friday that Suu Kyi, the 1991 Nobel peace laureate, had been hospitalized with severe diarrhea.

The country's police chief, Maj. Gen. Khin Yi, confirmed Suu Kyi had a stomach illness in the past few days but said it was not serious and denied she was hospitalized. He did not specifiy whether she had been taken to the hospital at all.

Thaung Htun, the New York-based U.N. representative for a self-styled Myanmar government in exile, said Suu Kyi was taken to the hospital sometime after 3 p.m. on Thursday after she called her physician because of diarrhea and weakness.

There was no immediate explanation for the discrepancy in dates for her hospital treatment.

Countrywatch:Myanmar

Suu Kyi has been in detention since May 2003 after her motorcade was attacked in northern Myanmar by a mob supporting the ruling junta. She was held first by the military, then transferred to house arrest. She is allowed virtually no contact with the outside world, although last month a senior U.N. official was allowed to meet her.

Suu Kyi is one of the world's most prominent political prisoners, and her release has been sought by many world leaders, including U.N. Secretary-General Kofi Annan and President Bush.

Thaung Htun said Suu Kyi, who has spent much of the last 16 years under house arrest, was delayed going to the hospital because her physician had trouble getting permission to see her.

"The physician should have a visit any time he thinks it's necessary," Htun said. "Delays should not happen because of asking permission from the authorities."

In Washington, the State Department said Friday it had heard reports of Suu Kyi's hospitalization but could not confirm them.

"We would call upon the Burmese government to provide Aung San Suu Kyi any and all medical assistance that she might need and to do so expeditiously and to ensure her safety during any treatment," spokesman Sean McCormack said.

"And we would also reiterate our call on the regime to release her from house arrest. It's sometimes difficult to get good, solid information in Burma, just because of the nature of the place. But we are quite concerned about the reports." Myanmar is also known as Burma.

Britain's Foreign Office also expressed concern on Friday.

"We've heard reports, we're very concerned about them but we're not able to confirm anything yet," a spokesman for the British Foreign Office said, speaking on condition of anonymity in keeping with government policy.

Myanmar's junta took power in 1988 after crushing vast pro-democracy demonstrations in Myanmar, formerly known as Burma. In 1990, it refused to hand over power when Suu Kyi's party won a general election by a landslide.