A staff paper prepared for British Prime Minister Tony Blair (search) eight months before the invasion of Iraq (search) concluded that U.S. military officials were not planning adequately for a postwar occupation, The Washington Post reported.

"A post-war occupation of Iraq could lead to a protracted and costly nation-building exercise," authorities of the briefing memo wrote, according to the Post. "As already made clear, the U.S. military plans are virtually silent on this point. Washington could look to us to share a disproportionate share of the burden."

The eight-page memo was written in advance of a July 23, 2002, meeting at Blair's Downing Street offices, the Post said in Sunday editions.

It said the memo and other internal British government documents were originally obtained by Michael Smith of the London Sunday Times and that excerpts made available to the Post were confirmed as authentic by British sources who sought anonymity because they were not authorized to discuss the matter.

The Post said the introduction to the memo — "Iraq: Conditions for Military Action" — said U.S. "military planning for action against Iraq is proceeding apace," but that "little thought" has been given to, among other things, "the aftermath and how to shape it."

The July 21 memo was produced by Blair's staff in preparation for a meeting with his national security team two days later that has become controversial since last month's disclosure of official notes summarizing the session.

According to those minutes — known as the Downing Street Memo (search) — British officials who had just returned from Washington said the Bush administration believed war was inevitable and was determined to use intelligence about weapons of mass destruction to justify the ouster of Saddam Hussein.

Blair denied at a news conference with President Bush last week that intelligence was manipulated to justify the war.