The Pentagon is planning to charge six detainees at Guantanamo Bay for the September 11 terrorist attacks on America and to seek the death penalty. Defense Department spokesman Bryan Whitman said an announcement of the charges could come Monday. A second official said that military leaders also will seek the death penalty for the attacks that killed nearly 3,000 Americans. Among those held at Guantanamo is Khalid Sheik Mohammed, the suspected mastermind of the attack six years ago in which hijacked planes were flown into buildings in New York and Washington, D.C. Five others are expected to be named in sworn charges. "The department has been working diligently to prepare cases and bring charges against a number of individuals who have been involved in some of the most grievous acts of violence and terror against the United States and our allies," Whitman said. Prosecutors have been working for years to assemble the case against suspects in the attacks in New York and Washington that prompted the Bush administration to launch its global war on terror. "The prosecution team is close to moving forward on referring charges on a number of individuals," Whitman said, declining to name the defendants. The New York Times reported in Monday edition that the others are Mohammed al-Qahtani, the man officials have labeled the 20th hijacker; Ramzi bin al-Shibh, said to have been the main intermediary between the hijackers and leaders of Al Qaeda; Ali Abd al-Aziz Ali, known as Ammar al-Baluchi, a nephew of Mr. Mohammed, who has been identified as Mr. Mohammed's lieutenant for the 2001 operation; Mr. al-Baluchi's assistant, Mustafa Ahmed al-Hawsawi; and Walid bin Attash, a detainee known as Khallad, who investigators say selected and trained some of the hijackers.