General Clark has called for a rethink on strategy
The former commander of Nato forces in Europe, General Wesley Clark, says American policy has "created chaos" in Iraq.
General Clark said the fundamental problem was the US tendency to fight states to get at "terrorists", rather than take on the "terrorists" themselves.
"We may have given Osama Bin Laden the recharge he needed to rebuild his arsenal and his ranks," he told the BBC's World Today programme.
General Clark is being encouraged to become a Democratic candidate for next year's presidential election, but has not yet announced if he will stand.
His criticisms coincided with a warning from the US administrator in Iraq, Paul Bremer, that the country would need tens of billions of dollars to rebuild its shattered infrastructure.
The bill to overhaul essential services would reach almost $30bn, on top of the estimated $1bn per week the US already spends on its forces in Iraq, he said.
President George W Bush has pledged "no retreat" in Iraq, saying US-led forces are making good progress in restoring order and insisting Iraq is part of the wider war on terror.
But General Clark expressed reservations about waging war on a country that he did not believe was "particularly linked to terrorism" or an "imminent danger".
He said the war should have resulted in restored Iraqi relations with the UN and Nato, finding weapons of mass destruction and ensuring Iraq would "not become a hotbed of international terrorism".
"We are drawing in terrorists. We have created chaos in Iraq," he said.
America should have concentrated its efforts on the "fundamental problem" of fighting "terrorism", he argued.
"What I have seen again and again is a tendency to want to attack states to get at terrorists rather than dealing with the harder problem of getting the terrorists themselves."
He said America should rethink its strategy on Iraq, and work to ensure Iraqis could take back control of their borders, security and reconstruction.
Bremer says some $30bn is needed to restore basic services
General Clark said he would announce in the coming days if he would stand as a candidate in next year's presidential elections.
The situation in Iraq is fast becoming an issue for next year's election, the BBC's Justin Webb reports from Washington.
Mr Bush's speeches have been branded "empty rhetoric" by opposition candidates, and his popularity ratings have fallen.
The number of American deaths since the end of major combat operations on 1 May has now surpassed the number killed during the war - 139 compared to 138.