The United States must do more to win the peace after successful wars, in order to prevent insurgencies like the one raging in Iraq, a new report issued by the Council on Foreign Relations said Wednesday.

"Nation-building is not just a humanitarian concern, but a critical national security priority that should be on par with war-fighting," said an independent task force chaired by former national security advisors Sandy Berger and Brent Scowcroft.

Their report recommended that post-war reconstruction, known as 'nation building' required as much planning, money and manpower as initial combat operations.

"The failure to take this phase of conflict as seriously as initial combat operations has had serious consequences for the United States, not just in Iraq but, more broadly, for international efforts to stabilize and rebuild nations after conflict," the report said.

In Iraq, a dearth of pre-war planning had left the United States ill-equipped to deal with security, governance and economic problems after the conflict, giving impetus to the insurgency, the report said.

The Bush administration came to power frowning at the 'nation building' bias of the Clinton administration, but after the September 11 attacks in 2001, found its policy prescriptions turned upside down, and embarked on multi-billion dollar reconstruction efforts in Iraq and Afghanistan.

The CFR panel also called for the establishment of a standing multilateral reconstruction trust fund worth one billion dollars, under the auspices of the Group of Eight nations.

The report called for the president's national security advisor to be formally tasked with overseeing coordination between civilian and military sectors of nation building and with overarching policy.

It called on the president and secretary of defense to make stability and reconstruction as important for the armed forces as high intensity combat operations.

The State Department, shut out of much of Iraq's immediate post-war construction, should lead all civilian nation building, the CFR report said, with its coordinator elevated to undersecretary of state rank.

Berger served as national security advisor under president Bill Clinton.

Scowcroft had the post under president Gerald Ford and president George Bush — the current president's father — and created a stir in the run-up to the Iraq war by coming out against an invasion.