Hungary has begun building a second line of fence along its southern border with Serbia, a government spokesman said on Monday, a move likely to exacerbate criticism from some of the country’s EU partners. A barbed-wire fence is already in place, erected in 2015, when Hungary was part of the main overland route for hundreds of thousands of migrants and refugees, many fleeing the war in Syria. Prime Minister Viktor Orban’s right-wing government considers migration to be one of the largest threats to the status quo in the EU. But officials in Brussels and some other EU centers are distressed by some of his go-it-alone policies. A European Parliament committee was due on Monday to discuss the state of fundamental rights in Hungary.