GENEVA - The UN human rights chief Navi Pillay has called on the United States government close down the Guantanamo detention center as she says it breaches international law.

In a statement Friday Pillay said, "The continuing indefinite incarceration of many of the detainees amounts to arbitrary detention and is in clear breach of international law."

Commissioner for Human Rights Pillay said, "I am deeply disappointed that the U.S. government has not been able to close Guantanamo Bay, despite repeatedly committing itself to do so."

The incarceration center is at the Guantanamo Bay U.S. Naval Base in southeastern Cuba.

Pillay referred to a current hunger strike by Guantanamo detainees which she described as a "a desperate act," but "scarcely surprising."

She noted that four years ago she warmly welcomed President Barack Obama's announcement immediately after his inauguration he was placing a high priority on closing Guantanamo and setting in motion a system to safeguard the fundamental rights of the detainees.

The detention center started in response to the September 11, 2001 attacks on the United States.

Still, the former South judge who has presided over war crimes said she welcomed a White House spokesman's reiteration of this commitment on March 27, citing Congressional legislation as the prime obstacle.

The UN commissioner said some of the detainees had been "festering in this detention center for more than a decade."

"This raises serious concerns under international law. It severely undermines the United States' stance that it is an upholder of human rights, and weakens its position when addressing human rights violations elsewhere," said Pillay.

The U.N. official said that apparently about half of the 166 detainees still held in detention had been cleared for transfer to home countries or third countries for resettlement.

"Yet they remain in detention at Guantanamo Bay," she said.

She said Guantanamo detainees accused of crimes should be tried in civilian courts, noting that military commissions "do not meet international fair trial standards" despite improvements since 2009.

As far back as February 2005 the main governing body of the World Council of Churches, its central committee, said it was "deeply concerned by the continued unconscionable and illegal detention of over 600 foreign nationals, mostly Muslims, at the Guantanamo Bay Naval Base."

The WCC urged the U.S. government immediately to grant legal rights accorded to detainees "as outlined in the amicus curiae brief to which the NCCC-USA (National Council of Churches of Christ in the USA), together with other national and international non- governmental organizations."