The United States is increasing the quality of intelligence given to U.N. weapons experts in Iraq as the United Nations bolsters its inspection team to act more quickly on the information, American officials said Saturday.

The arrival of 15 additional inspectors last week brought their total to 113. President Bush's national security adviser, Condoleezza Rice, wants 250 to 300 on the ground in Iraq, though the United States has not specified a time frame, a senior administration official said.

In the next two weeks, as the inspectors grow in number, the United States will provide more detailed intelligence reports, said the official, speaking on condition of anonymity.

Two administration officials said the United States has been continuously providing the United Nations with intelligence on Iraqi weapons sites.

The United Nations has pressed for more.

Chief U.N. weapons inspector Hans Blix urged the United States and Britain to hand over any additional evidence they have about Iraq's secret weapons programs.

He said the inspectors need intelligence because Iraq's declaration on the state of its weapons programs leaves so many unanswered questions that it is impossible to say confidently that its claim to have no weapons of mass destruction is accurate.

The United States and Britain have given briefings to inspectors on what they think the Iraqis have, but what inspectors really want to know is where weapons-related material is stored, Blix told the BBC.

One U.S. official said the administration was reluctant to provide information as detailed as the United Nations seeks for fear that inspectors would not be able to act immediately on it.

U.S. intelligence officials are also concerned that information could leak, jeopardizing information-gathering sources and other methods. The Pentagon fears that handing over such intelligence could tip off Iraq on likely bombing targets.

Blix said he planned to give the United States and Britain assurances that intelligence material would be protected. He said his inspectors, who are searching for chemical, biological and long-range missile programs, have between 500 and 1,000 sites to visit.

The administration's current strategy is to increase pressure on inspectors to seek interviews with Iraqi weapons scientists outside of Iraq to gain new intelligence and provide evidence that could be used against Iraqi President Saddam Hussein.