At least 34 sites in Las Vegas appear on videotapes seized from the New York apartment of a Pakistani man arrested in North Carolina, but the commentary on the tapes has yet to be translated from Urdu to English, so authorities do not know whether they represent a surveillance effort, FBI special agent Ellen Knowlton said Thursday.

Seven videos making up "many, many hours" of footage arrived Thursday from the New York FBI office, she said. A cursory review of the material showed it was "similar to what someone might bring home from a vacation," she said at a news conference also attended by Nevada Gov. Kenny Guinn, Las Vegas Mayor Oscar B. Goodman and other law enforcement and civic leaders.

The tapes were seized from the home of Kamran Akhtar, also known as Kamran Shaikh, after his July 20 arrest in Charlotte by police who were suspicious about his filming of skyscrapers there. He was detained on a charge of being in the United States illegally, and videotaped footage he had taken of tall buildings in several cities was discovered.

Knowlton declined to specify which Las Vegas sites appear on the tapes but acknowledged that several buildings are casinos. She noted that two of the tapes had no Las Vegas sites on them but probably were sent to her office because they showed casinos in other cities.

Guinn said the hastily called news conference was an effort to quell suspicion that local leaders would withhold information from the public about a terrorist threat. Las Vegas officials this week denied claims in internal FBI memos, reported by the Associated Press, that they had ignored or dismissed similar threats in the past because of fears that the threat of terrorism could damage the tourism mecca's economy.

In another case involving an alleged surveillance tape, law enforcement officials confirmed on Thursday the discovery of evidence that could raise new doubts about the convictions of members of an alleged terrorist cell in Detroit.

In a trial last year, prosecutors alleged that a videotape showing Disneyland, Las Vegas casinos and New York landmarks appeared to be terrorist surveillance, and it was found when the four defendants in the case were arrested.

But after the trial, a Tunisian immigrant who appears on the tape and who was arrested on immigration charges told authorities that the footage was taken during a college student trip, a law enforcement official said. The new account was turned over to defense attorneys this summer, the official said.

The witness's account is the latest blow to the Detroit case, which resulted in three convictions -- two of them on terrorism charges -- and was hailed by Attorney General John D. Ashcroft as a victory in the war on terrorism. But a special prosecutor has since been assigned to the case amid allegations that government lawyers failed to turn over evidence to the defense.

"New information and evidence has come to our attention that we were obligated to share with the defense," Justice Department spokesman Mark Corallo said.