"Active duty elements are postured on military bases in the National Capitol Region but are not in Washington, D.C.," Pentagon spokesman Jonathan Rath Hoffman said in a statement.
He said the troops were on "heightened alert status" but "are not participating in defense support to civil authority operations."
Senior defense officials had said on June 1 that units would be moving into the Washington region.
The troops include military police and those with engineering capabilities, along with an infantry battalion, Hoffman said.
