The opposition leader toured the Caracas neighborhood, observed damage to buildings and spoke with residents who suffered human and material losses.
Miller will replace Susie Wiles effective November 9. He moves up from deputy chief of staff after years of influence over the president's immigration agenda.
The U.S. secretary of state is demanding institutional, economic and security changes before a vote, while relatives of political prisoners ask Washington to press for further releases.
The secretary of state says he will remain in the administration until January 2029 and rejects reports that he is preparing a presidential campaign.
The U.S. official linked the 14ymedio director's detention with other recent cases involving Adelth Bonne, Camila Acosta and Henry Constantín.
The package covers eight companies and two individuals and restricts operations involving five oil tankers connected with crude transport.
