Italian security chiefs on Tuesday approved a plan to put 4,800 soldiers on the streets throughout the country to help guard against potential militant attacks, the Interior Ministry said.
A statement after a meeting of military and security officials said they would guard sensitive sites and targets until at least June.
Italian media said about 500 would be deployed in Rome, where army troops already help guard diplomatic missions and residences, the capital's synagogue and Jewish schools.
The troops are expected to be deployed at tourist venues such as archaeological sites and monuments.
The measures come after attacks by gunmen who killed two people in Copenhagen on Saturday and 17 people in Paris last month.
Security officials consider Rome particularly sensitive because it is home to the Vatican.
In the past, Islamist websites have posted vague threats against Pope Francis and the Roman Catholic Church, but Interior Minister Angelino Alfano said at an event with Vatican officials on Tuesday there was no specific threat.