Amid low public support for his handling of the Iraq war, U.S. President George W. Bush on Tuesday tried to link the rampant violence in Iraq to the al-Qaida terrorist organization.

"Al-Qaida in Iraq is a group founded by foreign terrorists, led largely by foreign terrorists and loyal to a foreign terrorist leader: Osama bin Laden," Bush said at the Charleston Air Force Base, South Carolina, one day after Democratic presidential candidates called at a debate in the city for withdrawal from Iraq.

"The merger between al-Qaida and its Iraqi affiliate is an alliance of killers and that is why the finest military in the world is on their trail," Bush said.

In his speech, Bush cited declassified intelligence to demonstrate that al-Qaida's operation in Iraq was a direct threat to the United States, and criticized lawmakers for calling for pulling American troops out of Iraq.

"I've presented intelligence that clearly establishes this connection" (between Iraq violence and al-Qaida), Bush said.

"Some say that Iraq is not a part of the broader war on terror... They claim that the organization called al-Qaida in Iraq is an Iraqi phenomenon, that it's independent of Osama bin Laden and that it's not interested in attacking America," he said.

"That would be news to Osama bin Laden," Bush said.

U.S. intelligence has showed that al-Qaida had no active cells in Iraq when the United States launched war against Iraq in March 2003, and that the group's operation in Iraq is much larger now than before the war.

Despite efforts to rally support for his war policy, the U.S. public see Bush as intransigent on Iraq and prefer that the Democratic-controlled Congress make decisions about a possible withdrawal of U.S. forces, a new poll showed.

The Washington Post-ABC News poll published on Tuesday found 55percent of those surveyed said they trust congressional Democrats on the war, compared with 32 percent who said they trust Bush. And by 2 to 1, Americans said Congress, rather than the president, should make the final decision about when to withdraw U.S. forces from Iraq.

Overall attitudes about the war in Iraq continue to be decidedly negative, with more than six in 10 saying that given the costs, the war was not worth fighting, and 55 percent said they support legislation that would set a deadline of next spring for the withdrawal of U.S. forces from Iraq, according to the poll.