Amid the greater scrutiny of foreign influence in the United States, the FBI has taken an expanded role in efforts to ensure lawyers, lobbyists and political consultants are fully revealing their advocacy for government clients, a move that observers said brings a new intensity to compliance reviews that have traditionally been handled by Justice Department staff.

This year, FBI personnel began joining Justice Department officials in inspections authorized under the Foreign Agents Registration Act, or FARA, a decades-old law requiring the disclosure of lobbying and other influence work for foreign governments. FARA enforcement ramped up over the past three years, as part of the special counsel’s investigation of Russia’s interference in the 2016 presidential election.