Washington  - From ages 13 to 24, the young Tibetan nun suffered daily beatings and deprivations from her Chinese jailers in the Tibetan capital Lhasa.

Ngawang Sangdrol's original crime - chanting slogans like "Free Tibet" - earned her a three-year sentence in 1992. A year later, it grew to 23 years after she and other jailed nuns smuggled out a secret recording of activist songs.

Family visits during the 11 years were limited to one relative for no more than five minutes a month, she told Deutsche Presse-Agentur dpa.

Now at age 31, Sangdrol, who was released from prison in 2003 under intense international pressure, is still fighting mad.

"The Chinese government took the best years of my life," she told a crowd of Free Tibet activists earlier Monday outside the White House.

The rally aimed to pressure US President Barack Obama to take up the cause of China's repression in Tibet and spearhead a multilateral effort on behalf of human rights in the world's highest mountainous kingdom.

The noon event coincided with midnight in Tibet, where Tuesday marks the 50th anniversary of the failed uprising against Chinese rule and the flight of the Dalai Lama into exile.

A strong breeze whipped the dozens of US and traditional yellow, blue, red and white Tibetan flags, which are forbidden by Chinese authorities inside Tibet.

Nearly 200 activists, some dressed in native costumes of red, grey, purple and green silk, stopped singing and talking for two minutes at the stroke of noon to commemorate the deaths of resistance fighters and monks over the decades.

Sangdrol told the crowd how electro-shock torture started when "I was still only 13 years old," with a device that her jailers first promised was a telephone to call her family, then placed inside her clothing to hurt her.

"China rules Tibet with brutal occupation," she told the crowd in English.

Sometimes, guards at the Drapchi Prison in Lhasa would forbid her allotted monthly visit from a relative as a form of punishment, Sangdrol told dpa.

After the rally, she joined other activists from 26 US states who lobbied Congress for their cause. She met with Nancy Pelosi, speaker of the House of Representatives, who held a Tibet rights reception with actor Richard Gere, chairman of the international campaign for Tibet.

Slender and dark-haired, Sangdrol said in the interview that she still suffers from prison-related illnesses, which at times leave her bed-ridden. She lives in New York, where she is studying English in an adult-education programme.

"I believe that what I have been through, I have done a lot for for the Tibetan issue. I'm not sure how much more I can contribute," she said through a translator. "But I'm committed to the Tibetan issue until there is a resolution."

As is often the case with political prisoners released before special events, Sangdrol's liberation in 2003 came weeks before Chinese President Jiang Zemin was to meet with former president George W Bush at his ranch in Crawford, Texas.

From prison, she went to her family's home.

"But I was being watched," she said. "I did not feel I had freedom."

After several months, US government officials picked her up and brought her to the United States. Much of the rest of her family, who are committed Free Tibet activists, have since scattered around the world, where they continue their political work.

Information is difficult to come by, and foreign reporters are rarely allowed access to the remote Tibetan region. Tibetan activists in the US count at least 600 political prisoners whose names can be confirmed.

"I totally feel their pain and understand," she told dpa. "I urge them to take care of themselves and their bodies to continue this long fight. This is not like a family issue that can be solved easily. No one knows how long it will take." (dpa)