New restrictions on news media access are going into effect at the detention center on the US base at Guantanamo Bay, Cuba.

The commander of the US military's Southern Command says he is limiting the frequency and length of media visits to the prison. Marine Gen. John F. Kelly says he will also no longer allow "routine" media tours inside the two camps where most prisoners are held.

Journalists have often visited on tours that lasted several days and included being allowed to view prisoners inside recreation areas of the main camps.

Kelly told The Associated Press on Thursday that the limits are in part aimed at avoiding conflicts with visits by members of Congress and foreign delegations.

The changes do not apply to the war crimes tribunals.