Sen. John McCain, top Republican on the Armed Services Committee, has placed a hold on the nomination of Gen. James Clapper to be the nation's next Director of National Intelligence.

The Arizonan's spokeswoman, Brooke Buchanan, tells Fox, "Senator McCain requested a specific report from Mr. Clapper and until that report is provided, Senator McCain will continue to hold his nomination." Buchanan would provide no further details on the content of the report.

This move means Senate Majority Leader Harry Reid, D-NV, will either have to file cloture on the nomination or wait until the situation between Clapper and McCain is resolved, a decision that could leave the top intelligence post vacant until mid-September, when the Senate returns from its summer recess.

Reid spokesman Jim Manley tells Fox that the concerns aren't just with McCain, "The White House is working hard to address the concerns being raised by some Republicans."

Clapper's nomination received the unanimous approval of the Intelligence Committee last week.