Federal authorities have interviewed more than 100 people in two separate investigations into the public disclosure of classified national security information, the start of a process that could take months or even years, according to officials familiar with the probes.

Law enforcement officials cautioned that they were only in the early stages of the investigations, and that they could prove inconclusive. FBI agents have already interviewed Attorney General Eric H. Holder Jr. and FBI Director Robert S. Mueller III. It is likely White House officials also will be contacted, but it remains unclear whether they have been interviewed yet…

The pace of the investigations is partly driven by the large number of government officials who had access to the material that was disclosed and who now must be interviewed, officials said. But that slow pace is also butting up against increasing urgency on Capitol Hill, where Republican lawmakers are alleging that the White House has purposefully disclosed classified information to reporters to burnish President Obama’s national security credentials ahead of the November election.