The department of Homeland Security and Defense announced 10 days ago more than 500 troops would help with border interdiction by Aug 1.
It isn't known when any troops will be deployed to enforce border security, a National Guard spokesman told The Arizona Republic.
"We won't have any units deployed by Aug. 1," said Lt. Valentine Castillo, a public affairs officer. "We don't yet know when troops will actually arrive."
U.S. Homeland Security Secretary Janet Napolitano previously wrote in a guest column for the newspaper that 524 Arizona National Guard troops would be assigned to the area.
A spokesman at the National Guard Bureau in Arlington, Va., told the newspaper statements previously released about the deployment were "over-interpreted."
"In a general sense, Guard members will begin the process of receiving required training on or about the first of August," spokesman Jack Harrison told the Republic.
The Arizona National Guard is reportedly still screening and training volunteers.