WASHINGTON — The CIA Director, General Michael Hayden, said today that the alleged Syrian nuclear reactor destroyed by an Israeli airstrike in September would have produced enough plutonium for one or two bombs within a year of becoming operational.

American intelligence and administration officials publicly disclosed last week their assessment that Syria was building a covert nuclear reactor with North Korean assistance. They said it was modeled on the shuttered North Korean reactor at Yongbyon, which produced a small amount of plutonium. The Syrian site, they said, was within weeks or months of being operational.

“In the course of a year after they got full up they would have produced enough plutonium for one or two weapons,” General Hayden told reporters after a speech at Georgetown University.

Almost all reactors produce plutonium, even those dedicated to peaceful purposes, according to the president of the nonprofit Institute for Science and International Security, David Albright. Mr. Albright analyzed commercial satellite imagery of the bombed facility last fall and surmised then it was a nuclear reactor.

Neither America nor Israel told the International Atomic Energy Agency about the Syrian site until last week, about a year after they obtained what they considered to be decisive intelligence: dozens of photographs from a handheld camera that showed both the interior and exterior of the mysterious compound in Syria’s eastern desert.

From the CIA’s perspective, that intelligence was not America’s to share with the U.N. nuclear watchdog, General Hayden said.

“We’ve made it clear we did not have complete control over the totality of the information because obviously it was the result of a team effort,” he said. “One has to respect the origin of the information in terms of how it is used.”

The head of the U.N. nuclear watchdog agency chastised America on Friday for withholding information on the alleged Syrian reactor. One of the IAEA’s missions is to try to prevent nuclear proliferation, and it depends on member states for information.

A senior administration official told reporters last week that America kept the information secret after the Israeli strike because it feared revealing it might provoke Syria to strike back at Israel.