Senior U.S. officials tell ABC News that in recent months there have been secret contacts between the Iranian government and the leadership of al Qaeda. It's a development that has caught the attention of top officials in the White House, the Pentagon and the intelligence community.

According to U.S. officials familiar with highly sensitive intelligence on this issue, the contacts are on the status of high-level al Qaeda operatives, including two of Osama Bin Laden's sons, who have been under house arrest in Iran since 2003. The officials don't believe Iran will allow these operatives to go free, but said they don't know Iran's motivation for initiating the talks.

"The Iranians know there would be hell to pay if these guys were set free," a U.S. official told ABC News.