The head of President George W. Bush’s cultural advisory committee stepped down this week in protest over the United States failure to stop the looting of Baghdad’s National museum, according to a letter released Thursday.

Martin Sullivan said in a letter to Bush dated on Monday he was resigning as chairman of the President’s advisory committee on cultural property, a position he had held since 1995.

“The reports in recent days about the looting if Iraq’s National Museum of Antiquities and the destruction of countless artifacts that document the cradle of Western civilisation have troubled me deeply, a feeling that is shared by many other Americans,” he wrote.

Describing the looting as a tragedy, Sullivan said that it was not prevented “due to our nation’s inaction.”

The 11-member committee is made up of experts and professionals in the art world who are appointed to three-year terms. Two are museum representatives, two are experts in archaeology and ethnology, three are specialists in worldwide art trade and four others are designated based on their areas of expertise.

A source close to the committee, speaking on condition on anonymity, said that another committee member, Gary Vikan, was also stepping down.

Sullivan serves as executive director of the historic Saint Mary’s City commission, dedicated to one of the first British colonies, in the state of Maryland. Vikan is director of the Walters Art Gallery in Baltimore, Maryland.

Baghdad’s museum, which housed one of the world’s greatest collections of artifacts from early Mesopotamian civilisations, was ransacked by looters in the anarchy that followed US forces’ entry into Baghdad.

US defence secretary Donald Rumsfeld said earlier this week that Washington was offering rewards for their return of items from the museum or assistance in their recovery.

But critics have faulted US forces for failing to intervene in the extensive pillaging of the capital and other Iraqi cities after President Saddam Hussein’s regime collapsed. Some have even suggested that the 'stand and watch' approach was part of a deliberate policy to ensure the total breakdown of Iraqi civil society in order to prepare public opinion for a pro-US administration