Washington ? The FBI has spent more than a year covertly investigating, including with the use of electronic surveillance, whether a Pentagon analyst funneled highly classified material to Israel, officials said Saturday. Prosecutors still were weighing whether to bring the most serious charge of espionage.

Charges could be brought in the case as early as this week, said two federal law enforcement officials speaking on condition of anonymity. The case has taken so long in part because of diplomatic sensitivities between the United States and its close ally Israel, they said.

Although the information involved — material describing Bush administration policy toward Iran — was described as highly classified, prosecutors could determine that the crime involved falls short of espionage and could result in lesser but still serious charges of mishandling classified documents, the officials said.

They said the still-classified material did not detail U.S. military or intelligence operations and was not the type that would endanger the lives of U.S. spies overseas or betray sensitive methods of intelligence collection.

The target of the probe was identified by the two officials as Larry Franklin, a senior analyst in a Pentagon office dealing with Middle East affairs. Franklin, who did not respond to a telephone message left at his office Saturday, formerly worked for the Defense Intelligence Agency.

Efforts to find a home telephone number were unsuccessful.

In a statement late Friday, the Defense Department, without identifying anyone by name, said the inquiry involved someone at the “desk officer level, who was not in a position to have significant influence over U.S. policy. Nor could a foreign power be in a position to influence U.S. policy through this individual.”

Franklin works in an office overseen by Douglas J. Feith, the defense undersecretary for policy. Feith is an influential aide to Defense Secretary Donald Rumsfeld whose previous work included prewar intelligence on Iraq, including purported ties between Saddam Hussein’s regime and al-Qaida terrorism network.

In August 2003, Franklin and a Pentagon colleague were in the news after it was disclosed they had met two years earlier with Manuchar Ghorbanifar, who was among the Iranians who suggested to the Reagan administration in the 1980s that profits from arms-for-hostages deals be funneled into covert arms shipments to U.S.-backed Contra rebels battling the leftist Nicaraguan government.

The investigation centers on whether Franklin passed classified U.S. material on Iran to the American Israel Public Affairs Committee, the highly influential main Israeli lobbying organization in Washington, and whether that group in turn passed them on to Israel. Both AIPAC and Israel deny the allegations.