TAMPA – The Palestinian Islamic Jihad planned an attack inside the United States, but it might have been thwarted by federal law enforcement, an FBI agent testified Tuesday afternoon.

Agent Kerry Myers said all information about the plot was classified and he could not discuss it.

He made the revelation early in his cross-examination as a witness in the terror-support trial of former University of South Florida professor Sami Al-Arian and three other men. U.S. District Judge James Moody later ordered prosecutors to present evidence about the plot to him during a closed meeting in his chambers to determine whether defense attorneys should have access to it.

Defense attorney William Moffitt had asked Myers whether the Islamic Jihad ever committed a terrorist attack outside Israel or the occupied territories.

It has not, but its leaders threatened to attack the United States three times, Myers said.

During a rapid-fire exchange in which both men’s voices rose, Moffitt asked Myers whether anyone ever acted on those threats.

“I can tell you there was a plot to commit terrorist acts in the United States,” he said. “It was interdicted, I believe.”

Moffitt asked when that happened.

“It’s classified,” Myers said, drawing chuckles from defendants’ relatives and supporters in the courtroom gallery.

During its 10-year investigation of Al-Arian and defendants Ghassan Ballut, Hatim Fariz and Sameeh Hammoudeh, the FBI intercepted 472,239 telephone calls on 18 tapped lines, Myers said. None involved any discussion of an attack against the United States. Nor did any conversation show advanced knowledge of any attack in the Middle East.

Myers, the FBI case agent, has been on the stand for four weeks, mostly sitting silently as prosecutors read from hundreds of transcripts of intercepted calls that are in evidence. They included calls from 1994 showing Al-Arian struggling to keep the Islamic Jihad from falling apart during a financial crisis and calls showing other defendants funneling money to the Middle East.

Defense attorneys say the money went to needy people, including orphans, but prosecutors say it went to arms of the Islamic Jihad. Prosecutors accuse Al-Arian of serving as secretary on the Islamic Jihad’s Shura council, a board of directors for the group.

Moffitt’s cross-examination was just getting started Tuesday afternoon. He has not yet asked Myers about any specific conversation or challenged any government translation.

He emphasized two U.S. designations of the Palestinian Islamic Jihad as a terrorist group. The first was by the Treasury Department after an executive order signed by President Clinton in January 1995. The second, by the State Department, came in October 1997.

They made it illegal to engage in transactions with the Islamic Jihad and establish when it became a crime to provide material support to the group.

Al-Arian is far less visible on the intercepts after federal agents raided his home and offices in November 1995. The searches came about three weeks after a director at Al-Arian’s think tank, Ramadan Shallah, was appointed the Islamic Jihad’s new commander.

After jurors were dismissed for the day, Moody advised Myers to avoid answers that lead to classified information. Should the situation arise again, Moody said, the lawyers can discuss it quietly at the bench.

He also offered advice to defense lawyers.

“Beware of open-ended questions,” he said.