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The State Department (search) won't turn over more internal documents requested by Senate Democrats investigating John R. Bolton's (search) fitness to be U.N. ambassador, a spokesman said Monday.

"I don't think we're stiffing anybody here," State Department spokesman Tom Casey said. "We feel we've given all of the information that's required under those circumstances."

Separately, a top intelligence officer prepared to brief several lawmakers about the embattled nominee's requests for the names of U.S. officials whose communications were picked up by the secret National Security Agency. Both Democrats and Republicans have sought details about Bolton's pursuit of the NSA information.

The Senate Foreign Relations Committee is scheduled to vote Thursday on Bolton's nomination. The committee's senior Democrat, Sen. Joseph Biden of Delaware, complained over the weekend that the State Department had failed to provide documents related to Bolton's current job as the department's arms control chief. Democrats say they need the information before the vote, and Biden has hinted that he could force a delay.

The State Department and the U.S. Agency for International Development have turned over about 500 pages of documents to the committee, including e-mails, memos, telegrams and drafts of speeches, according to figures from the State Department's congressional affairs office. Various intelligence agencies have provided about 125 pages of documents.

Congressional aides said the Republican chairman of the Senate Intelligence Committee and the panel's top Democrat are expected to be briefed Tuesday. Deputy National Intelligence Director Gen. Michael Hayden will probably be among those explaining the NSA intercepts. Hayden is a former head of the NSA. It is not clear whether the separate Foreign Relations Committee would also hear details of Bolton's requests.

Democrats want to know if Bolton was spying on other government officials he suspected of disagreeing with or undermining his views on sensitive topics such as Cuban and Syrian weapons capabilities.

At his confirmation hearing last month, Bolton acknowledged asking for a few names of U.S. officials whose communications — presumably telephone and e-mail — were recorded during NSA surveillance operations. It later emerged that Bolton made 10 such requests.

In a letter to Secretary of State Condoleezza Rice on Saturday, Biden said the department had turned over material that answered questions posed by the committee's Republican chairman but not by Democrats.

All eight Democrats on the committee have indicated they plan to vote against Bolton, citing his past hostility to the United Nations or his conduct in his current job. Democrats are looking for evidence that Bolton twisted government intelligence to suit his conservative views or mistreated lower-level analysts who tried to raise red flags.

In an interview Monday, Rice dismissed allegations that Bolton tried to pressure intelligence analysts to change their assessments.

"I see nothing that suggests that John was anything but an interested consumer of intelligence and asked difficult questions," Rice said in a cable news interview. "I don't think there's anything wrong with someone, a policy-maker, asking difficult questions of the intelligence community."

Foreign Relations Committee Chairman Richard Lugar, R-Ind., has predicted Bolton will win committee support by a 10-8 party-line vote and said there is no reason to postpone the vote a second time. Lugar put it off last month after a moderate Republican, Sen. George Voinovich of Ohio, said the committee should investigate Bolton further.

Besides his testimony last month, Bolton has had 23 private meetings with senators and answered 157 written questions, according to the congressional affairs office figures. Democrats have complained that some of the answers were incomplete or brusque, and some were merely a yes or no without elaboration.

The Foreign Relations Committee interviewed 31 people, including 13 current State Department employees.

A transcript of an interview last week with Robert Hutchings, former chairman of the National Intelligence Council, was released Monday. Hutchings described a testy debate between Bolton and intelligence analysts over Syrian weapons programs.

"I wouldn't say he was making up facts. Let's say that he took isolated facts and made much more of them to build a case than I thought the intelligence warranted," Hutchings said. "It was a sort of cherry-picking of little factoids and little isolated bits that were drawn out to present the starkest-possible case."

On Monday, 43 former U.S. ambassadors added their names to a letter signed earlier by 59 ex-ambassadors opposing the nomination. Most served in Republican administrations.