WASHINGTON -- Arizona Sen. John McCain joined three other senators Thursday in sending a letter to President Barack Obama, expressing concern over reports the Administration may try the mastermind of the 9/11 terrorist attacks and other alleged war criminals in civilian courts.

The senators said they believe that military commissions are the appropriate forum to try suspected terrorists and war criminals.

Joining McCain in signing the letter were fellow Republican Lindsey Graham of South Carolina and Democrats Joe Lieberman of Connecticut and Jim Webb of Virginia.

Trying Mohammed and others in civil courts "would treat the war on terrorism as a law enforcement operation, rather than a war, and would treat its alleged perpetrators as common criminals, instead of violators of the law of war," the senators wrote.

The letter said: "Military commissions have played a time-honored role in our country, from the time General George Washington relied on them during the Revolutionary War. The revised military commission procedures contained in S. 1390, the National Defense Authorization Act for Fiscal Year 2010, not only meet but surpass the fundamental standards of fairness and due process required by our Supreme Court, the Geneva Conventions, and the rules of the International Criminal Court.

"Given the robust procedural and substantive rights now provided by this revised system of military commissions, and the sensitive nature of much of the evidence that would be brought forth, we are disturbed that your Administration has expressed a clear preference for prosecuting alleged war criminals in federal district courts in Virginia, New York, and the District of Columbia."

The senators said they believe revised military commission procedures will become law in the coming months and that prosecutors can be handled at Guantanamo Bay, Cuba, where the suspects are currently held.

"The individuals detained at Guantanamo Bay are not held because of violations of domestic criminal law," the senators wrote. "They are detained because they have been found to be members of al-Qaida or other terrorist organizations, and have taken up arms against the United States of America."

The senators said, "The forum for their trial should reflect the fact that these detainees were captured as part of a military operation and face trial for violations of the law of war. As a result, we urge you to prosecute these suspected war criminals by military commission at Guantanamo Bay."