Former president George W. Bush's advisers focused on toppling Saddam Hussein's regime as soon as he took office and discussed how to justify a war in Iraq shortly after invading Afghanistan in 2001, official documents showed Wednesday.

A few hours after the September 11 attacks in 2001, then defense secretary Donald Rumsfeld spoke of attacking Iraq as well as Osama bin Laden, according to notes of a meeting on that day, newly declassified papers show.

Rumsfeld told a Pentagon lawyer to go to his deputy to get "support" showing a supposed link between the Iraqi regime and Al-Qaeda's founder, according to the papers posted by the Washington-based National Security Archive, an independent research institute.

The US government has since acknowledged that Saddam's regime had no role in the 9/11 attacks.

In June and July of 2001, senior administration officials seized on intercepted aluminum tubes as proof that Iraq was pursuing nuclear weapons, even before a preliminary assessment of the tubes, according to two State Department memos to then secretary of state Colin Powell.

One memo states the US government's interest in "publicizing the interdiction to our advantage" and "getting the right story out" about the tubes, which were soon found to have no nuclear connection.

Confronting Iraq was also the focus of a July 2001 memo to the national security adviser at the time, Condoleezza Rice, with Rumsfeld urging a high-level meeting on policy towards Baghdad.

Voicing concern that sanctions were proving a failure and that Iraq's air defenses were improving, Rumsfeld warned: "Within a few years the US will undoubtedly have to confront a Saddam armed with nuclear weapons."

Forecasting an optimistic outcome far from the result the Iraq war produced, Rumsfeld said that Washington's image in the region and the world would benefit from toppling Saddam.

"If Saddam's regime were ousted, we would have a much-improved position in the region and elsewhere," he wrote. "A major success in Iraq would enhance US credibility and influence throughout the region."

Another document shows Rumsfeld discussing war plans for Iraq just two months after the 2001 US invasion of Afghanistan.

In a meeting with the then head of US Central Command, General Tommy Franks, the defense chief tells him to ready forces for the "decapitation" of the Iraqi regime.

In talking points dated November 27, Rumsfeld lists possible triggers the Bush administration could use to start a war, including Iraqi military action against the US-protected enclave in northern Iraq, discovery of ties between Saddam and 9/11 or recent anthrax attacks and disputes with UN weapons inspections.

In a December 18, 2001 memo, the State Department's analytical unit warns that France and Germany will likely oppose an invasion of Iraq without concrete proof that Baghdad was behind the 9/11 attacks.

The same memo warns that British support for a US war would come at a political cost for the prime minister, Tony Blair, and could trigger a backlash from the country's Muslim population.

Backing the US war "could bring a radicalization of British Muslims, the great majority of whom opposed the September 11 attacks but are increasingly restive about what they see as an anti-Islamic campaign," the memo states.

The documents posted Wednesday were released under a Freedom of Information request.