An Obama administration inquiry into a leak of information about a covert U.S.-Israeli cyber-sabotage effort against Iran has stalled because of national-security and diplomatic concerns, a media report says.

The Washington Post reported that a former vice chairman of the Joint Chiefs of Staff – Ret. Marine Gen. James E. Cartwright – is suspected of leaking to The New York Times information about a classified plan to impair Iran's ability to enrich uranium.

Neither the U.S. nor Israel has acknowledged such an effort, the paper said.

But the paper said that if prosecutors pressed the case, they would face major obstacles, particularly the potential that Israel might oppose disclosure of the operation's details in court.

That in turn could worsen Israel-U.S. relations, which are already severely strained because the two countries disagree about how to prevent Iran from gaining nuclear weapons, the paper reported.

In addition, Obama administration officials worry that bringing such a case could complicate the nuclear negotiations with Iran that are under way, the Post reported.

The FBI, Justice Department and White House declined to comment to the paper. Cartwright's attorney told the paper that the retired officer has done nothing wrong and would do nothing to harm U.S. security. The lawyer said he's had no contact with prosecutors for more than a year.