WASHINGTON—The Justice Department will resume investigating foreign-bribery cases with a narrowed focus on matters that relate to U.S. strategic interests, including buttressing the ability of American firms to compete for business overseas.

Deputy Attorney General Todd Blanche announced the changes after a four-month review triggered by President Trump’s order earlier this year freezing corruption investigations. Trump said at the time that enforcement of a federal antibribery law, the Foreign Corrupt Practices Act, puts American firms at a disadvantage to foreign rivals that can engage in conduct forbidden in the U.S.