BERLIN — Under pressure from a growing nationalist movement, the government in Denmark on Thursday reintroduced stringent checks on its borders with Germany and Sweden, dealing a major setback to one of the European Union’s most popular and tangible measures: the freedom to cross frontiers without controls.

It was the second major assault within weeks on an agreement originally signed in 1985 at Schengen, a town in Luxembourg near France and Germany, and has gone a long way toward abolishing border controls across much of Europe.

Nicolas Sarkozy, the French president, and Silvio Berlusconi, the Italian prime minister, proposed amending the Schengen accord this month in an effort to deal with the wave of refugees fleeing to Italy from North Africa and the Middle East.

At a meeting of the European Union’s 27 interior ministers in Brussels on Thursday, 15 called for changes to the rules. Although they did not spell out what kind of amendments they wanted, E.U. diplomats said they reflected the growing influence of populist Euro-skeptic parties like the one in Denmark that demanded the change.