The United States has announced it will boost security at government buildings after threats from Islamist groups and following two attacks last week in Canada that killed two soldiers.
The "precise actions" and "precise locations" were not specified in a statement by US Secretary of Homeland Security Jeh Johnson.
Mr Johnson said additional measures would vary, shift and "be continually reevaluated."
He also called the action "a precautionary step, to safeguard US government personnel and facilities, and the visitors to those facilities.
"The reasons for this action are self-evident," Mr Johnson said, citing "continued public calls by terrorist organisations for attacks on the homeland and elsewhere" as well as the two attacks last week in Canada.
Both of the attacks came as Canada deployed fighter jets to join US-led air strikes on the self-styled Islamic State group (IS) in Iraq.
Police say both assailants were converts to Islam with alleged extremist views.
Canada is a member of the alliance Washington has forged of Western and Arab nations to combat IS, which seized large parts of Syria and Iraq in recent months, committing widespread atrocities.
The group called for foreign fighters to join them and promoted attacks by disaffected Muslims on Western targets.
"Given world events, prudence dictates a heightened vigilance in the protection of US government installations and our personnel," Mr Johnson said.
