Updated

The Hungarian government says a second fence being built on the Serbian border to stop migrants will be completed by May 1.

Janos Lazar, Prime Minister Viktor Orban's chief of staff, said Thursday that a 10-kilometer (6.2-mile) test section of the second fence, which is equipped with motion sensors and other surveillance tools, has produced "spectacular" results, preventing anyone from breaching it.

Hungary built fences protected by razor wire on the borders with Serbia and Croatia in 2015, at the height of the migrant flow toward Western Europe. Some 400,000 migrants passed through Hungary in 2015 before the fences were erected.

The second fence, as well as proposals to place all asylum seekers in border camps made of shipping containers, are part of Hungary's new anti-migration efforts.