Former CIA Director Robert Gates, President Bush's nominee for defense Secretary, criticized the handling of the war in Iraq and said he will improve Pentagon postwar planning if he is confirmed.

Gates also endorsed the idea of engaging Iran and Syria for help in stabilizing increasingly violent Iraq, an opinion at odds with Bush's.

Gates made the comments in response to a questionnaire from the Senate Armed Services Committee, which is to hold a confirmation hearing next week.

"War planning should be done with the understanding that post-major combat phase of operations can be crucial," Gates said in a 65-page written response submitted to the committee Tuesday.

"If confirmed, I intend to improve the department's capabilities in this area," he said in answer to a question about what he would have done differently. "With the advantage of hindsight, I might have done some things differently."

Gates also appeared to subtly criticize the invasion of Iraq.

"I believe the use of pre-emptive force should be based on very strong evidence," he said when asked about incorrect intelligence saying that Saddam Hussein had weapons of mass destruction. "It is a decision that must not be taken lightly," Gates added.

He also said that "hard questions" must be asked about intelligence.

Asked whether the United States should engage Iran and Syria for help in stabilizing Iraq, Gates endorsed the idea but said talks need not be on a one-on-one basis.

A bipartisan commission led by former Secretary of State James A. Baker III and former Representative Lee H. Hamilton is widely expected to call for regional talks as part of its recommendations for a way forward in Iraq.

"Even in the worst days of the Cold War, the U.S. maintained a dialogue with the Soviet Union and China, and I believe those channels of communication helped us manage many potentially difficult situations," the nominee said of proposals for talks with Iran.