Tourists traveling between Spain and Italy are caught in the middle of an escalating ideological feud over European border security involving Italian Prime Minister Giorgia Meloni and Spanish Prime Minister Pedro Sánchez.

Madrid on Saturday restored border controls on ships and flights arriving in Spain from Italian ports and airports, suspending passport-free travel between the two countries. Spain said the move was necessary to protect its citizens from “the persistent irregular migration pressure suffered by the transalpine country.”

The move was an unmistakable retaliation for the checks that Italy has imposed on travelers arriving from Spain since Aug. 1. Rome enacted those measures in response to the mass arrival of people in the Spanish exclave of Ceuta, citing fears that the unauthorized migrants could cross the Strait of Gibraltar and take advantage of the passport-free Schengen area to travel onward to Italy and elsewhere in the EU.