UNITED NATIONS (AP) ― U.N. Secretary-General Ban Ki-moon joined the United States, the European Union and human rights groups Wednesday in expressing concern at last week’s death of a detained Chinese human rights activist in a Beijing hospital.

Last month, Human Rights in China quoted Cao Shunli’s lawyer as saying she suffered from tuberculosis, liver disease and other conditions and was not receiving proper medical treatment. China’s Foreign Ministry has denied that she died because of lack of medical care.

U.N. deputy spokesman Farhan Haq said Ban shares the “deep concern” of human rights chief Navi Pillay that Cao was detained for seeking to allow the public to contribute to a report reviewing human rights in China for the U.N. Human Rights Council and was saddened at her death Friday.

Cao, a human rights lawyer, staged a two-month sit-in with other activists outside China’s Foreign Ministry in Beijing and was detained on Sept. 14 as she tried to leave for Geneva to attend a U.N. session for human rights advocates. She was formally arrested in October on suspicion of “picking quarrels and provoking troubles” and was held in a detention center until she was transferred to a hospital in critical condition on Feb. 19.

Her death was raised Tuesday at the Human Rights Council in Geneva by the U.S., the EU, and a group of U.N. human rights experts.

Pillay’s office said Cao’s initial disappearance, arbitrary detention, failing health and denial of medical care were brought to the attention of the U.N. experts who issued a statement on Oct. 16 expressing alarm.

“A formal response from the Chinese authorities indicating that she had no serious health problems and had access to medical care was questioned by the experts” the U.N. rights office said.

The experts urged Chinese authorities to investigate the circumstances leading to Cao’s death promptly.

“The death of Ms. Cao is a tragic example of the results of criminalization of the activities of human rights defenders in China and reprisals against them,” the experts said in a statement.

“It is unacceptable that civil society activists pay the ultimate price for peaceful and legitimate interaction with the United Nations and its human rights mechanisms.”

U.S. State Department spokesman Jen Psaki said Saturday in a news release that the United States was “deeply disturbed” at reports of Cao’s death and had repeatedly raised concerns about her detention and deteriorating health with Chinese authorities.