Updated

Widening their inquiry of the terrorist attacks beyond the FBI and the CIA, lawmakers are examining the National Security Agency's Sept. 10 intercept of at least two messages in Arabic that suggested a major event was to take place the next day.

Intelligence agencies aren't sure if the messages intercepted on Sept. 10 were actually a warning of the attacks at the World Trade Center and Pentagon, an intelligence source said Wednesday.

The messages, which have been brought to the attention of House and Senate intelligence committee members, were not translated until Sept. 12.

As the congressional inquiry wrapped up its third week of closed-door hearings, the NSA's director, Lt. Gen. Michael V. Hayden, underwent a second day of questioning alongside FBI Director Robert Mueller and CIA Director George Tenet.

The panel is investigating the events surrounding the Sept. 11 attacks, problems in counterterrorism efforts and how future attacks can be averted.

Even if the Sept. 10 NSA intercepts were a reference to the next day's attacks, they provided no information that authorities could have acted on, the intelligence source said. The mere mention of a time was insufficient to provide any clue of what was to come, the source said.

The Washington Post reported that contents of one of the communications was, "The match is about to begin," while the other stated, "Tomorrow is zero hour."

A U.S. intelligence official, while declining to comment on the NSA intercepts, said a piece of raw intelligence that contains only a date provides little useful information.

The official said that both before and after Sept. 11, U.S. intelligence frequently has received threat information that consists of only a date and a vague notion something will happen — and then, nothing happens.

Much of the questioning Wednesday addressed problems that have hindered intelligence-gathering, such as communications problems among agencies, a shortage of linguists and the difficulty of dealing with massive amounts of intercepted communications.

Rep. Sherwood Boehlert, R-N.Y., said that "no one prior to 9-11 tried to sugar coat any threat, but there wasn't the specificity. ... We didn't know exactly where or when."

"Much of the system was just dysfunctional" in terms of agencies sharing information, said Sen. Ron Wyden, D-Ore. "Terrorists are like burglars going through a neighborhood. They rattle on every door and find a point of vulnerability."

The intelligence hearings are scheduled to be opened to the public Tuesday, but several lawmakers say that could be postponed. They said the committee and staff need to sift through huge amounts of information and are working with the Justice Department to see what information can be presented in public.

Rep. Ray LaHood, R-Ill., said he doubts public proceedings will begin next week.

"We want to make sure that when we go public that the right people are there and are well prepared," he said.