The resignation of Central Intelligence Director George Tenet has prompted bipartisan calls for reforming U.S. intelligence agencies.

Mr. Tenet's decision to step down comes amid controversies over intelligence lapses relating to Iraq and the September 11, 2001, terrorist attacks on the United States.

In a speech to CIA employees, Mr. Tenet said his decision is purely personal, but he acknowledged the difficulties his agency faced in recent years.

?Our record is not without flaws,? he said. ?The world of intelligence is uniquely a human endeavor, and as in all human endeavors, we all understand the need to always do better. We are not perfect, but one of our best kept secrets is that we are very, very, very good. Whatever our shortcomings, the American people know we constantly evaluate our performance, always strive to do better, and always tell the truth.?

At the White House, President Bush said he is sorry to see Mr. Tenet go.

?He has been a strong and able leader at the agency. He has been a strong leader in the war on terror,? Mr. Bush said.

Mr. Bush's presumed Democratic challenger for president, Senator John Kerry of Massachusetts, issued a written statement saying Mr. Tenet's resignation is an opportunity to reshape the U.S. intelligence community and create a new director of national intelligence to oversee all intelligence agencies.

He called on the Bush administration to take responsibility for what he called "significant intelligence failures," which have occurred during Mr. Tenet's tenure.

Similar comments were made by the top Democrat in the House of Representatives, Congresswoman Nancy Pelosi of California.

?There certainly were intelligence failures in the Iraq operation, particularly in the months preceding the invasion,? she said. ?There have been many other failures, as well. I do not believe the resignation of George Tenet should be the only response to those failures.?

Republicans, too, see an opportunity for reforming intelligence agencies. The chairman of the Senate Intelligence Committee, Senator Pat Roberts of Kansas spoke to the issue shortly before the announcement of Mr. Tenet's resignation.

?I think that the community is somewhat in denial over the full extent, and I emphasize full extent, of the shortcoming of its work in Iraq, and also 9-11 [the terrorist attacks on the United States on September 11, 2001],? he said. ?We need fresh thinking within the community, especially within the Congress, to enable the intelligence community to change and adapt to the dangerous world in which we live, and for all of us, all of us, to look in the mirror, and honestly examine our collective performance over the past decade.?

Mr. Tenet has been under fire for months in connection with intelligence failures related to the U.S.-led war in Iraq and the September 11th attacks. Critics say he and other members of the administration failed to fully appreciate the threat posed by al-Qaida prior to the terrorist attacks on New York and Washington, and overestimated the threat from Iraq.

But Mr. Tenet is also credited with building morale and providing stability at the CIA, which had three directors in the five years before him.

Senator Charles Schumer is a New York Democrat. He says, ?I think Tenet did more than anybody else to try to move the CIA along into the 21st century, when so many obstacles had been thrown in its path previously.?

At a House committee hearing, the director of the Federal Bureau of Investigation, Robert Mueller, praised Mr. Tenet's service at the CIA.

?In my experience working with him, he has sought at every turn to bridge the gap between the CIA and the FBI, and he has always been concerned about one thing, one goal, and one goal only, and that is the safety of the American public,? he said.

Mr. Tenet, who was nominated by President Bush's Democratic predecessor Bill Clinton in 1997, is one of the longest-serving CIA directors in U.S. history.

Mr. Tenet will serve until mid-July, when Deputy CIA Director John McLaughlin will temporarily take over, until a successor is nominated by the president and confirmed by the Senate.