The United States says the site was a secret plutonium reactor being built with the help of North Korean scientists. Syria insists the area was an unused military site.
Photos displayed at a congressional hearing in April purported to show the inside of a hidden nuclear facility and rods to control the heat in a nuclear reactor, similar to those in North Korea. The administration said it withheld the pictures out of concern that Syria could retaliate against Israel, perhaps sparking a broader war in the Middle East, according to the New York Times.
More recent satellite images suggest Syria dismantled what was left of the facility after the Sept. 6, 2007, airstrike, essentially removing all evidence.
ElBaradei said his team had negotiated the visit with Syria for months.
"We are therefore treating this information with the seriousness it deserves and have been in discussions with the Syrian authorities since this information was provided to the agency with a view to arranging a visit to Syria at an early date to verify, to the extent possible at this stage, the veracity of the information available to the agency," ElBaradei said, adding a warning to Syria to cooperate fully.
A senior diplomat told the Associated Press that inspectors were interested in two other locations in Syria with possible undeclared nuclear facilities.
However, the chief nuclear inspector also had harsh words for Israel and the United States, which gave Israel the go-ahead to strike the site last year.
"It is deeply regrettable that information concerning this installation was not provided to the agency in a timely manner and that force was resorted to unilaterally before the agency was given an opportunity to establish the facts, in accordance with its responsibilities under the Nonproliferation Treaty and Syria's Safeguards Agreement," ElBaradei said.
Israel and Syria have been in quiet peace negotiations for months, but the talks, facilitated by Turkish mediators, are reportedly stuck on such issues as the Israeli occupation of the Golan Heights area, and Syria's relationship with Iran and terrorist-linked groups.