Homeland Security Secretary Jeh Johnson said the Federal Protective Service will enhance its presence at various sites in Washington DC and elsewhere.
The action has been described as a precautionary step to safeguard US government personnel and facilities.
It comes one week after a gunman opened fire in Ottawa, killing a soldier.
"The reasons for this action are self-evident: the continued public calls by terrorist organisations for attacks on the homeland and elsewhere, including against law enforcement and other government officials, and the acts of violence targeted at government personnel and installations in Canada," Mr Johnson wrote in a statement on Tuesday.
"Given world events, prudence dictates a heightened vigilance."
The homeland security chief did not provide details as to which of the more than 9,500 federal US facilities will see additional security, claiming such information is "law-enforcement sensitive".
The announcement comes just hours after Canadian Prime Minister Stephen Harper spoke at a funeral for Cpl Nathan Cirillo, 24, killed by gunman Michael Zehaf-Bibeau last week.
"May time ease the searing pain of today," Mr Harper told mourners.
Cirillo was standing guard unarmed at Canada's war memorial when Zehaf-Bibeau, 32, opened fire.
The gunman then entered Canada's parliament and fired dozens of shots before being killed by Sergeant-at-Arms Kevin Vickers.
The Canadian authorities earlier said the gunman was radicalised but had no ties to Middle Eastern Islamist extremists.

Bryony Freestone, 19, from Little Houghton, Northampton, died off the island of Koh Chang on 14 August.
Kurtis Middleton, who had been with the Exeter University student for more than three years, said she taught him "to seize life by the horns".
Her twin Sophie said Bryony recently said "if she were to die right now, she would have lived her life to the full".
Bryony, a student at the university's Penryn Campus in Cornwall, was said to be "talented, dedicated and hugely popular".
Describing her as "my beautiful Bryony", her boyfriend said: "You were more than just my partner, you were my best friend and over our three years and three months we had together I've grown into a much better person, simply through knowing you."
Her sister agreed, saying: "You were the most vibrant, passionate, happy person I have ever known, enthusiastic about absolutely everything.
"I will endeavour to live my life the best I can for her."
Mr Middleton added: "Bry taught me how to seize life by the horns and make the most of every moment... we could all learn a lesson from her.
"Sleep tight Bryony, I love you with all my heart."
Earlier this week the Foreign Office confirmed it was supporting the family of a British national "who sadly died in Thailand on 14 August".
The US has announced bolstered security measures at government buildings across the nation in the wake of an attack on Canadian parliament.
[NEXT_CONCEPT]
The boyfriend of a student who drowned in Thailand has spoken of the "big open space where [she] should be".