A key Republican lawmaker is blaming Central Intelligence Agency Director George Tenet for the faulty intelligence on Iraq's weapons program that President Bush cited in part to justify the war in Iraq. But Democrats say it is the president's credibility that is on the line.

A political battle is intensifying in Washington over who to blame for the false intelligence on Iraq's weapons.

At issue is President Bush's statement in his State of the Union address last January in which he said Iraq had sought significant quantities of uranium in Africa.

In a rare about-face this week, the White House acknowledged the information was incorrect. The move followed reports that the CIA warned the administration last year that documents alleging Iraq had tried to buy uranium from Niger were false.

Traveling in Africa, Mr. Bush and his National Security Advisor Condoleezza Rice both said that U.S. intelligence agencies had cleared the State of the Union address.

Although Ms. Rice said the President has confidence in Director Tenet, the Republican chairman of the Senate Intelligence Committee, Senator Pat Roberts of Kansas, said the CIA chief is to blame.

In a statement, Mr. Roberts said Mr. Tenet is the President's principal adviser on intelligence matters. In his words, Mr. Tenet "should have told the president" about the false information, but it "appears that he failed to do so."

Mr. Tenet was originally appointed by Mr. Bush's Democratic predecessor, Bill Clinton.

There was no comment from the CIA.

Congressional Democrats, for their part, said Mr. Bush is ultimately responsible.

Senator Bob Graham of Florida, the former chairman of the Intelligence Committee who is seeking his party's nomination for president next year, said in a statement: "Mr. President, stop trying to pass the buck. You made the baseless claim, you should take responsibility."

Other Democrats stepped up their calls for an independent probe into the matter.

"The credibility of our President is on the line, and I believe he should move forward as quickly as possible to call for a full investigation," said Senator Dick Durbin of Illinois, a senior member of the Senate Intelligence Committee. "We should be able to point to those people responsible for putting that misleading language into the State of the Union address. They should be held accountable, and they should be dismissed."

The issue is expected to top the agenda at a closed hearing of the Senate Intelligence Committee next Wednesday.