A liberal congressman has demanded a chance to visit with accused secrets leaker Pfc. Bradley Manning, who is being held in US military custody.

"As you know, I am concerned about reports of his treatment while in custody that describe alarming abuses of his constitutional rights and his physical health," Rep. Dennis Kucinich (D-OH) wrote in a letter to Defense Secretary Robert Gates Friday.

He continued, "His care while in the custody of the Department of Defense is the responsibility of the U.S. Government and as a member of the House Committee on Oversight and Government Reform it is my duty to conduct effective oversight."

Recent reports have suggested that Manning's condition has declined visibly during six months in solitary confinement. Kucinich earlier in the week demanded that the Army publicly reveal Manning's mental health.

"If true, the Army’s treatment would obviously constitute 'cruel and unusual punishment' in violation of the Eighth Amendment to the United States Constitution," Rep. Kucinich wrote in a previous letter to Gates.

Kucinich urged that Manning be immediately provided with a mental health specialist should the accusations of unfair treatment before his deployment to Iraq prove correct.

"At the very least, the Army must explain the justification for confining someone with mental health problems under conditions that are virtually certain to exacerbate those problems and explain the danger he now presents that only these extreme conditions of confinement can avoid," he added.

Kucinich's letter came in response to The Washington Post's report on Pfc. Manning, an Army intelligence analyst accused of being a source of the WikiLeaks documents. The report indicated that the Army deployed Manning to Iraq in spite of a mental health screening that recommended he remain at home.

In Iraq, Manning's mental health continued to deteriorate, the report indicated, to the point where he was demoted in rank for assaulting another soldier. Since his arrest in May 2010, Manning has been held in intensive solitary confinement at a prison in Quantico, Va.

Quoting from Glenn Greenwald's December 2010 report on Manning's condition, Kucinich wrote,"In sum, Manning has been subjected for many months without pause to inhumane, personality-erasing, soul-destroying, insanity-inducing conditions of isolation similar to those perfected at America's Supermax prison in Florence, Colorado:  all without so much as having been convicted of anything."

Kucinich also quoted from a recent "Open Letter" from the Psychologists for Social Responsibility, issued in protest of Manning’s incarceration. The letter said that the group determined Manning's confinement fits the definition of "cruel, unusual and inhumane treatment" and thereby violates US law.

In January, two activist reporters who tried to deliver a petition protesting Manning's treatment were detained against their will at Quantico. A few days earlier, Manning had been placed on suicide watch for two days against the wishes of the prison's psychologist.

Many of Manning's defenders say the US is trying to use its leverage against the Army private to pressure him into testifying against WikiLeaks founder Julian Assange, something the New York Times suggested last month.

Manning has been held in some form of solitary confinement for at least the past six months. He faces charges the Army says could result in up to 52 years in prison.

The United Nations' special rapporteur for torture has reportedly launched an investigation into complaints that Manning's treatment at Quantico amounts to torture.

This week, Amnesty International attempted to increase support to Manning by suggesting he may be a British citizen because his mother is reportedly Welsh by birth. However, Manning's lawyer said that his client considered himself an American citizen.

With reporting by Daniel Tencer.