WASHINGTON (CNN) -- Democratic presidential hopeful Barack Obama has been placed under secret service detail, according to a statement from the U.S. Secret Service.

"Secretary Chertoff has, after consultation with the congressional advisory committee, authorized the United States Secret Service, to protect presidential candidate Senate Barack Obama.

"As a matter of procedure, we will not release any details of the deliberations or assessments that led to protection being initiated. For security reasons we will not release the timing, scope or details of any protective operations."