The panel investigating the Sept. 11, 2001, attacks has unearthed evidence that al Qaeda leaders had postponed the operation from an intended date in the spring of that year because their lead hijacker was not ready, The Washington Post said on Tuesday.

Citing unidentified sources privy to the panel's findings, the Post reported that the operation's suspected mastermind, Khalid Sheikh Mohammed, who has been in U.S. custody since March 2003, convinced al Qaeda leader Osama bin Laden to delay the attacks from May or June.

Evidence of a date postponement, which was obtained from U.S.-held detainees, is expected to be discussed by the 10-member independent commission on Wednesday, as it holds its final public hearings this week into how al Qaeda pulled off its spectacular attacks against U.S. targets, the Post said.

Until now, the newspaper said, U.S. investigators have cited evidence that indicates the suicide hijackings that killed more than 3,000 people in New York, Pennsylvania and at the Pentagon probably were initially planned to be carried out on or about Sept. 11, and if there was an alternate date, it probably would have been later in the year.

The Post quoted an official who has seen the panel's draft report that has been circulated among government and commission officials as saying the findings are based on "intelligence coming in that they wanted an earlier date. It's something really new."

Although bin Laden wanted the hijackings to be carried out in May or June, he agreed to delay them because lead hijacker Mohammed Atta and his conspirators had not started reconnaissance flights until May, the Post quoted sources as saying.

The evidence suggests that the decision to delay the attacks came about for operational reasons and not in response to heightened security in the early summer of 2001, it said.

The panel, formally known as the National Commission on Terrorist Attacks Upon the United States, is due to present its findings on July 26 after a year and a half of work in which it heard from more than 1,000 people in 10 countries, including President Bush, some in closed sessions.

Source: CD/Agencies