The U.S. military has increased the threat level at bases across North America. Officials say the incremental boost will likely mean heightened vigilance and more random bag or vehicle checks.

The baseline level went from A to B, although most military installations — including the Pentagon — were already at a slightly higher level of protection than level A. There are four levels, A through D.

Army Col. Steve Warren says the increase was not triggered by a specific event. He says it was due to a generally heightened threat environment, which would include the recent terror threat and attempted attack surrounding a provocative cartoon contest in Texas.

The alert level was approved by Adm. Bill Gortney, head of U.S. Northern Command.