NEW LONDON, Conn. - U.S. President George Bush, stressing that Americans face an ongoing threat from terrorists, shared intelligence on Wednesday asserting that Osama bin Laden was working in 2005 to set up a unit inside Iraq to hit U.S. targets.

Much of the information Bush cited in a commencement address at the U.S. Coast Guard Academy described terrorism plots already revealed, but he fleshed out details and highlighted U.S. successes in foiling planned attacks.

Bush said that intelligence showed that in January 2005, bin Laden tasked Abu Musab al-Zarqawi, his senior operative in Iraq, to set up the cell to use Iraq as a staging ground for attacks in the United States. Al-Zarqawi was killed in Iraq in June 2006 by a U.S. airstrike.

This information expanded on a classified bulletin the Homeland Security Department issued in March 2005. The bulletin, which warned that bin Laden had enlisted al-Zarqawi to plan potential strikes in the United States, was described at the time as credible but not specific. It did not prompt the administration to raise its national terror alert level.

Bush, who is battling Democrats in Congress over spending for the unpopular war in Iraq, also said that in the spring of 2005, bin Laden instructed Hamza Rabia, a senior operative, to brief al-Zarqawi on an al Qaeda plan to attack sites outside Iraq. Around the same time, Abu Fajah al-Libi, a senior al Qaeda manager, suggested that bin Laden send Rabia to Iraq to help al-Zarqawi plan the external operations, he said. It is unclear whether Rabia went to Iraq.

Bush said that another suspected al Qaeda operative, Ali Salih al-Mari, was trained in Afghanistan and dispatched to the United States before the Sept. 11, 2001 terrorist attacks.

"Our intelligence community believes Ali Salih was training in poisoning at an al Qaeda camp in Afghanistan and had been sent to the United States before 9-11 to serve as a sleeper agent ready for follow-on attacks," Bush said.

Bush also talked about how in 2003, intelligence officials uncovered and stopped an aviation plot led by another suspected senior al Qaeda operative named Abu Bakr al-Azdi.

"Our intelligence community believes this plot was to be another East Coast aviation attack, including multiple airplanes that had been hijacked and then crashed into the United States," Bush said.

Frances Fragos Townsend, the White House homeland security adviser, said new details about the plots were declassified because the intelligence community has tracked all leads from the information, and that the players were either dead or in U.S. custody.

The Bush White House in the past has declassified and made public sensitive intelligence information to help rebut critics or defend programs or decisions against possibly adverse decisions in the Congress or the courts. On a few occasions, the declassified materials were intended to be proof that terrorists see Iraq as a critical staging ground for global operations.

Democrats and other critics have accused Bush of selectively declassifying intelligence, including portions of a sensitive National Intelligence Estimate on Iraq, to justify the U.S.-led invasion on grounds Saddam Hussein's regime possessed weapons of mass destruction. That assertion proved false.

"It would have been really helpful for the president to have been able to use this classified information earlier," Townsend said.

Using the information earlier would have allowed the president to use it to his political advantage, she said. "This is kind of late to be able to bring this to the game," she said, adding that intelligence officials needed time to exploit the information.