Some leading U.S. conservatives who advocated the U.S.-led invasion of Iraq in 2003 are now breaking ranks with the Bush administration over its handling of the post-invasion phase.

In an interview to be published in an upcoming issue of Vanity Fair magazine, several conservatives blame the current chaos in Iraq on the administration's incompetence.

Among them is Richard Perle, who chaired the influential Defense Advisory Board for the Pentagon at the time of the invasion.  He says President Bush is ultimately responsible for his administration failing to make good decisions.  Perle says he would not have advised an invasion had known how Iraq would turn out.

Another board member describes the administration's foreign policy team as "dysfunctional."

Meanwhile, an editorial to appear in four independent military newspapers calls on Mr. Bush to dismiss Defense Secretary Donald Rumsfeld.

The editorial says Rumsfeld "has lost credibility with the uniformed leadership, with the troops, with Congress and with the public at large." 

Mr. Bush said this week that the embattled defense chief would remain in the administration for the remaining two years of his presidency.

Some information for this report was provided by AP .