By DOUGLAS JEHL
WASHINGTON - A new report from the Central Intelligence Agency says that the Pakistani arms trafficking network led by A. Q. Khan provided Iran's nuclear program with "significant assistance," including the designs for "advanced and efficient" weapons components.
The unclassified version of report, posted today on the agency's Web site (www.cia.gov), does not explicitly say whether Mr. Khan's network had sold Iran complete plans for building a warhead, the network is known to have done with Libya and perhaps North Korea. But it suggests that American intelligence agencies now believe that the bomb-making designs provided by Mr. Khan's network to Iran in the 1990's were more significant than the United States government has previously disclosed.
In a recent closed-door speech to a private group, George J. Tenet, the former director of central intelligence, described Mr. Khan, the father of Pakistan's nuclear weapons program, as "at least as dangerous as Osama bin Laden" because of his role in providing nuclear technology to other countries. A tape recording of the speech was provided to The New York Times.
Until now, in discussing Iran's nuclear program, American officials have publicly referred only to the Khan network's role in supplying designs for older Pakistani centrifuges used to enrich uranium. But American officials have also suspected that the Khan network provided Iran with a warhead design. The C.I.A. report is the first to assert that the designs provided to Iran also included those for weapons "components."
The C.I.A. report to Congress is an annual update, required by law, on countries' acquisition of illicit weapons technology. The posting of the unclassified version on the agency's Web site today comes two days before a meeting in Vienna of the International Atomic Energy Agency, the United Nations' nuclear monitoring group, is to review the status of Iran's weapons program.
"The Report to Congress on the Acquisition of Technology Relating to Weapons of Mass Destruction and Advanced Conventional Munitions" is the first to be issued by the agency since last November. Its focus is the six-month period from July to December 2003, but it also discusses broader trends.
It does not mention what Secretary of State Colin L. Powell described last week as new intelligence about Iran's nuclear program, linking the country's missile program to its effort to find a way to deliver atomic weapons.
The report says the agency remains convinced that Iran is pursuing a clandestine weapons program, despite claims to the contrary by the Tehran government. It says that Iran's stated willingness with the I.A.E.A. is likely to prevent the Tehran government from using its declared nuclear sites to produce weapons, but warns that Iran could nevertheless use covert facilities for those purposes.
The warhead design provided to Libya by the Khan network was for an aging, crude Chinese model. Such a design would nevertheless provide Iran with important assistance in what American officials say is its quest to develop nuclear weapons, a goal they say the Tehran government could reach in the next several years.
The C.I.A. began to infiltrate Mr. Khan's network beginning in the late 1990's, according to the account Mr. Tenet is now spelling out in his speeches. That operation led to the unraveling of the Khan network's ties to Libya and the unmasking last year of Libya's illicit weapons program.
Mr. Khan remains in Pakistan, where he was pardoned last year by President Pervez Musharraf. Libya turned over the design to the United States early this year, and it is now being examined at the Department of Energy, the custodian of the American nuclear arsenal.
But American intelligence agencies are still pursuing questions about the extent of the role the Khan network played in providing assistance to North Korea, Iran and perhaps other customers. A recent report by the I.A.E.A. has noted "several common elements" between Iran's nuclear program and Libya's, which is being dismantled.
Mr. Khan directed Pakistan's uranium enrichment program for 25 years. His role as an illicit supplier of nuclear technology had been widely rumored, but was made public only late last year, when the United States and Britain reached an agreement with Libya that made public the extent of that government's weapons program.
In recent paid speeches, Mr. Tenet has provided new details about the C.I.A.'s role in unraveling the Khan network, according to people who have heard them. The speeches to private groups have been delivered on ground rules that they remain off the record, but a tape recording of remarks he made at a session in Georgia in September was provided to The Times by a person who was there.
In that speech, Mr. Tenet said that the C.I.A.'s role had stretched back to 1997, and that he had kept it secret within the government from everyone but President Bill Clinton and President Bush. Describing a "hidden network that stretched across three continents," Mr. Tenet said of Mr. Khan: "Working with British colleagues, we pieced together his subsidiaries, his clients, his front companies, his finances and manufacturing plants. We were inside his residence, inside his facilities, inside his rooms. We were everywhere these people were."
Mr. Tenet called the agency's role "one of the greatest success stories nobody ever talks about."
A classified version of the C.I.A. report has been provided to Congressional intelligence committees, administration officials said. The unclassified version that was made public today refers only obliquely to several sensitive subjects, including what American officials believe has been North Korea's recent success in building as many as a half-dozen additional nuclear weapons from plutonium extracted from spent fuel rods.
The unclassified report notes only that North Korea announced publicly in October 2003 that it was using the plutonium "for increasing the size of its nuclear deterrent forces."
The document restates long-standing concerns that outside experts, including a Pakistani nuclear engineer, may have provided assistance to the Qaeda terrorist organization as part of its quest to acquire nuclear weapons. "One of our highest concerns is Al Qaeda's stated readiness to attempt unconventional attacks against us," says the report, by the agency's Weapons, Intelligence, Nonproliferation and Arms Control Center.