US prosecutors said the indictment charges Steven Rosen, 63, the former foreign policy director for Aipac, with conspiracy to communicate national defence information provided by analyst Lawrence Franklin.
Rosen was also accused of helping Franklin pass on written classified information. Aipac's former senior Middle East analyst, Keith Weissman, 53, also was charged with conspiracy to communicate national defence information, prosecutors said.
The defendants disclosed the classified information to several members of the media, a senior fellow at a Washington, DC, think-tank and at least three foreign government officials, according to the indictment.
Israeli officials identified
Although the indictment did not identify any of the recipients, sources said they included officials who worked at the Israeli embassy.
Franklin, 58, who worked on the Iran desk within the Office of the Secretary of Defence at the time the government says he disclosed the information, had already been charged with disclosing top-secret information about potential attacks on US forces in Iraq to the two Aipac employees.
"We are disappointed that the government has decided to pursue these charges, which Mr. Weissman strongly denies"
John Nissikas, attorney for one of the lobbyists, Keith Weissman
He has also been charged with giving the information to an unidentified diplomat and to Rosen and Weissman, whom Aipac fired in April after having defended their conduct last year.
The indictment accuses Franklin of disclosing to a foreign diplomat classified information about a Middle Eastern country's activities in Iraq.
Passing on secrets
It said between August 2002 and June 2004, Franklin also gave the diplomat classified information relating to a weapons test conducted by a Middle Eastern country.
Sources familiar with the investigation have said the diplomat was an Israeli.
Franklin pleaded not guilty to the original charges.
Abbe Lowell, attorney for Rosen, said the charges were unjustified. "We expect that the trial will show that this prosecution represents a misguided attempt to criminalise the public's right to participate in the political process," he said.
Weissman's attorney, John Nissikas, said in a statement: "We are disappointed that the government has decided to pursue these charges, which Mr Weissman strongly denies."
Breaking the law
The Aipac is a pro-Israel lobbying
group in the US
Aipac issued a statement on Thursday saying it could not "condone or tolerate the conduct of the two employees under any circumstances".
Franklin faces a maximum sentence of 45 years if convicted on all counts, while Rosen faces a maximum sentence of 20 years and Weissman faces 10 years in prison, prosecutors said.
"When it comes to classified information, there is a clear line in the law", US Attorney Paul McNulty said.