The State Department had a pointed response Friday for the U.N.'s criticism that the U.S. did not come forward with information about Syria's clandestine nuclear reactor program: Get over it and start investigating.

"We would expect and hope that the IAEA (International Atomic Energy Agency) would investigate this matter," spokesman Sean McCormack told reporters. "The fact of the matter now is this is an issue that is worthy of investigation putting aside these questions of timing."

McCormack was responding to IAEA Director General Mohamed ElBaradei's complaint that the U.S. did not give his organization intelligence information sooner on what Washington says was a nuclear reactor in Syria being built secretly by North Korea.

• Click here to view photos.

ElBaradei's also chastised Israel for bombing the site seven months ago, in a statement whose strong language reflected anger at being kept out of the picture for so long.

The White House broke its silence about the issue on Thursday, just hours after top U.S. legislators — members of the House of Representatives Intelligence Committee — were briefed on the alleged reactor. U.S. intelligence officials said evidence included dozens of photographs taken from ground level as well as footage of the interior of the building taken by spy satellites after the Israeli strike.

The IAEA's mission includes trying to keep nuclear proliferation in check, and it depends on member states for information in trying to carry out that task. The agency is investigating allegations that Iran tried to make nuclear weapons, and it is using not only its own research but intelligence provided by the U.S. and other members of the 35-nation IAEA board.

"The director general deplores the fact that this information was not provided to the agency in a timely manner, in accordance with the agency's responsibilities under the nuclear Non-Proliferation Treaty, to enable it to verify its veracity and establish the facts," said an IAEA statement, issued a day after ElBaradei was briefed.

Additionally, "the director general views the unilateral use of force by Israel as undermining the due process of verification that is at the heart of the nonproliferation regime," it said.

Promising a follow-up, the statement said the IAEA "will treat this information with the seriousness it deserves and will investigate the veracity of the information," adding: "Syria has an obligation ... to report the planning and construction of any nuclear facility to the Agency."

John Rood, the U.S. undersecretary of state for arms control, briefed ElBaradei by telephone. Additionally, a senior U.S. official, who spoke on condition of anonymity because of the sensitivity of the matter, said a U.S. intelligence team was in Vienna to brief IAEA representatives.

A senior diplomat linked to the IAEA said ElBaradei had already let his displeasure be known to Rood, during the U.S. official's phone call, over the delay between the time the information became available to the U.S. and when he was informed of it. U.S. Congressional Intelligence Committee members also expressed anger Thursday over the seven-month time lapse before their committee was briefed.

In Washington, the State Department brushed aside elBaradei's complaint.

"The fact now is that the IAEA is being briefed, they are being provided the information and we believe that this is certainly an issue that merits close scrutiny and investigation by the IAEA," McCormack said.

"The fact of Syria having a nuclear reactor that is in violation of their NPT obligations in our estimation is something worthy of investigation by the IAEA," McCormack said, referring to the Nonproliferation Treaty. "And, certainly the Syrians as a member of the treaty should grant access to the IAEA to the site."

John Bolton, who has served as U.S. ambassador and before that held Rood's job at a time the U.S. was considering trying to push ElBaradei out from his position, said the IAEA's chief criticism is "entirely unwarranted."

"The IAEA was and remains unable to deal with regimes like Syria," he said in an e-mail to the AP. "Israel did what was necessary to defend itself, and the U.S. had no obligation to brief the IAEA in such a matter."

While U.S. undersecretary of state for arms control several years ago, Bolton was a chief ElBaradei critic at a time Washington was lobbying for ElBaradei's replacement because of his differences with the U.S. administration over how much of a nuclear threat Iran and Saddam Hussein's Iraq posed.

ElBaradei did not criticize Syria and North Korea. And U.N. Secretary-General Ban Ki-moon said he lacked "concrete information" on the issue. But the U.N. chief told reporters while on a visit to Vienna that "as a matter of principle, this proliferation of weapons of mass destruction ... is a serious source of great concern"

"(The) international community must work hard to prevent such proliferation," he said.

Repeating its previous stance, Syria denied the allegations Thursday.

But in Seoul, Kim Sook, South Korea's top nuclear envoy, said the allegations of nuclear cooperation between North Korea and Syria were credible and urged Pyongyang to fulfill a promise to declare all its atomic programs.

"We share the concern expressed by the U.S. government about the North Korean nuclear weapons program and nuclear proliferation activities," Kim told The AP in a telephone interview Friday.

Top U.S. intelligence officials who briefed reporters in Washington on Thursday said they had high confidence in the judgment that North Korea had aided Syria with a nuclear program whose aim was to produce plutonium. But they claimed only low confidence for the conclusion that it was meant for weapons development, in part because there was no reprocessing facility at the site — something that would be needed to extract plutonium from spent reactor fuel for use in a bomb.

The alleged reactor was within weeks or months of being functional when Israeli jets destroyed it, a top U.S. official told The Associated Press in Washington, speaking on condition of anonymity because of the sensitivity of the matter. The official said the facility was mostly completed but still needed significant testing before it could have been declared operational.

The Associated Press contributed to this report.