The head of the International Committee of the Red Cross on Friday deplored the refusal of the U.S. administration to allow its neutral delegates to visit people being held in secret detention.

In an unusually strongly worded statement, the agency known for its discretion expressed disappointment that Secretary of State Condoleezza Rice, Defense Secretary Donald Rumsfeld and other officials refused to yield to the demand.

"No matter how legitimate the grounds for detention, there exists no right to conceal a person's whereabouts or to deny that he or she is being detained," said Jakob Kellenberger, president of the ICRC, following a series of top-level meetings in Washington.

The ICRC is designated by the Geneva Conventions on warfare as the organization to visit prisoners of war. It is the only independent body the United States lets visit terror suspects detained in Iraq, Afghanistan and Guantanamo Bay, Cuba, but it has long been demanding access to detainees held in "undisclosed locations."

"Speaking after his meetings, Mr. Kellenberger deplored the fact that the U.S. authorities had not moved closer to granting the ICRC access to persons held in undisclosed locations," said an ICRC statement issued Friday.

U.S. officials contacted at the American mission to international organizations in Geneva said they had no immediate comment.

A State Department spokesman said previously that the U.S. government provides access to the vast majority of detainees under its control even though it doesn't regard al-Qaida members as covered by the Geneva Conventions. Spokesman Adam Ereli acknowledged last December that "there are some" detainees to whom the United States refuses to grant access.

The ICRC statement said the main objective of Kellenberger's visit was to gain agency access to all people held by the United States in the context of the fight against terrorism. It noted that it first raised the issue more than two years ago.

Kellenberger said in the statement that the ICRC would continue to seek access to these people "as a matter of priority" despite the "the disappointing lack of results and the current U.S. position."

The ICRC acknowledged that states may detain individuals for security reasons as well as in the framework of armed conflict or on criminal charges, but said all those held by the United States are entitled to a clear legal status and procedural safeguards.

The issue of secret detention centers and alleged CIA flights taking prisoners to them became subject of more intense international scrutiny after a report about them in the Washington Post last November.

Besides meeting with Rice and Rumsfeld, Kellenberger also held talks Thursday in Washington with National Security Adviser Stephen Hadley, Deputy Secretary of Defense Gordon England and other senior U.S. officials.