Ms Zhao was allegedly beaten by US homeland security officers at Niagara Falls, when they mistook her for a member of a drug-smuggling gang last week.

Mr Ridge said the alleged assailant would be charged and promised measures would be taken at the Canadian border to prevent similar incidents.

The apology came shortly after US Secretary of State Colin Powell wrote to his counterpart Li Zhaoxing to say he was disturbed by the 'unfair treatment' of Ms Zhao.

A US State Department spokesman also expressed regret at the 'apparent mistreatment' of Ms Zhao, adding that the US would continue to work to ensure that such incidents did not occur again.

The case has drawn little attention in mainstream US newspapers, but Chinese community groups in New York are rallying public support.

Liang Guanjun, president of New York United Chinese Association, an umbrella organisation of Chinese provincial community groups, said a protest and petition would be held in New York.

'Zhao's case is a serious violation of human rights, yet the American public and media have not shown much concern. We want to bring to their attention how serious the matter is and prevent any more Chinese citizens falling victim to US police brutality,' he said.

Ms Zhao has started medical treatment and filed an application for assistance with the Crimes Victims Board of New York State.

In Ms Zhao's home town of Tianjin , her mother Liu Wenmin told China Central Television she was heart-broken.

'It was the first time my daughter visited the US, a country which supposedly upholds freedom and human rights,' she said.