WASHINGTON – The White House is worried that the chief of the International Atomic Energy Agency may use a scheduled visit to the United Nations today as an opportunity to fan the flames of the missing Iraqi explosives story that Senator Kerry has touted in the last week of the election campaign.

On Friday, Secretary of State Powell phoned the director general of the U.N. atomic-energy agency, Mohammed El-Baradei, to discuss the investigation into the facility near Baghdad, Al Qaqaa, from which at least 377 tons of plastic explosives, formerly under seal, disappeared.

“They discussed the upcoming meeting in New York and the need to work together to find out the facts. It was noted that this was a story a lot of people were paying attention to. It was noted that this had become a public issue,” a State Department official who had received a read-out of the call told The New York Sun.

Another American official familiar with the discussion told the Sun that Mr. Powell warned Mr. ElBaradei to “steer clear” of the American elections when he presents his agency’s annual report to the General Assembly in New York today. That official was careful to stipulate that Mr. Powell did not accuse the Egyptian-born diplomat of leaking the story. Mr. ElBaradei himself said publicly last week that he was not the source of the original leak, which led to stories by the New York Times and CBS News.

“I think it is very likely that ElBaradei will not be able to resist making comments about U.S. responsibility for the missing explosives the day before the election,” an official of the Bush administration told the Sun yesterday.

Mr. ElBaradei and the Bush administration have feuded since the run-up to the Iraq war in March 2003, when the agency suggested that evidence the administration publicized about an Iraqi attempt to procure uranium yellowcake from Niger was forged. The Boston Globe reported Saturday that in April 2003, the Pentagon refused a request from the U.N. agency to send a team of experts to secure nuclear facilities in Iraq, including Al Qaqaa. The agency was brought in eventually, however, to monitor the Al Tuwaytha facility, a site where, in the aftermath of the war, bins of radioactive material were looted.

More recently, Mr. ElBaradei has publicly stated that Iranian violations of the nuclear nonproliferation treaty should not be referred to the U.N. Security Council, directly opposing the Bush administration’s stated position that they should. Recent intelligence gathered by American agencies also suggests that Mr. ElBaradei may have been coaching the Iranians on how to avoid international censure – a finding disputed inside the American intelligence community. The State Department, officials said, will not support Mr. ElBaradei’s bid for a third term as director general, nonetheless. Mr. El Baradei has said he will run for the office anyway.

While Mr. ElBaradei has said he did not leak the Al Qaqaa report to the Times or CBS, he did instruct his spokeswoman, Melissa Flemming, to talk last week with both CNN and the Associated Press, confirming that the agency was concerned about the missing cache of HMX, RDX, and PETN explosives. Those compounds are similar to the explosives used to blow up the Pan Am 103 jet over Lockerbie, Scotland.

Mr. ElBaradei’s agency also made public portions of an October 1 letter sent to it from Iraqi authorities. In it, they said the looting was due to a lack of security after the April 9, 2003, liberation of their country. A quotation to that effect was included in Mr. ElBaradei’s letter last Monday to the president of the Security Council.

Two Bush administration officials told the Sun yesterday that Mr. ElBaradei’s making public the report from Iraq’s Ministry of Science of Technology, given that the interim government is in no position to know how the explosives vanished, was unusual.

“How in the world would the interim government know what happened?” one of the American officials asked. “The IAEA gets information all the time of this nature. Rarely is it discussed in public.”

The Sun reported last week that U.N. weapons inspectors pleaded with the atomic-energy agency in 1995 to explode the cache of explosives at Al Qaqaa but were rebuffed at the time because the Vienna-based agency said the explosives were not solely for a nuclear-weapons program and could be used for industrial purposes.

The story of the missing explosives has become a talking point for Mr. Kerry and Democratic surrogates on the campaign trail, leading to a political commercial from the campaign accusing President Bush of incompetence in Iraq. On Friday, the Pentagon spokesman Larry DiRita stressed to reporters in a briefing about Al Qaqaa that the 377 tons of missing explosives represent a minuscule amount in comparison to the 400,000 tons of ordinance that coalition soldiers have exploded since the fall of Saddam Hussein’s regime. The spokesman also said there was “some apparent movement of heavy equipment in this facility at a time when only Saddam Hussein was in control of that facility, meaning after inspectors left the country and before U.S. forces arrived to begin the liberation of the country.”

On Friday Human Rights Watch sent out a press release claiming that senior researchers in the field had warned the Pentagon of other insecure military facilities. The executive director of the organization said Friday,” “Immediately after the fall of Baghdad, our researchers were finding massive stockpiles of weapons and explosives throughout Iraq. But when we informed coalition forces, they told us they just didn’t have enough troops to secure these sites.” Last Wednesday, a former Senate aide who helped unearth Iraqi documents on Mr. Hussein’s gassing of Kurds, Peter Galbraith, published an op-ed that blasted the Bush administration for allowing the looting. He said that on April 16, 2003, a mob looted Iraq’s equivalent of the country’s Centers for Disease Control, taking stocks of live HIV and the virus associated with black fever. “U.S. troops were stationed across the street but did not intervene because they didn’t know the building was important,” he wrote.