Hungary will stage a referendum on October 2 on a European Union decision that it - along with other member states - accept asylum seekers from the most heavily burdened EU countries under a quota system, Hungarian President Janos Ader said Tuesday.
Voters will be asked: "Do you want the European Union to be able, without consulting the [Hungarian] parliament, to order the immigration of non-Hungarian citizens into Hungary?"
The Hungarian government had signalled plans for the referendum for months, despite EU objections. Budapest recently got the green light from the country's constitutional court.
Under the EU plan, the bloc is redistributing asylum seekers across all member states, as opposed to letting countries of first call such as Italy and Greece carry the lion's share of the burden.
The plan was approved by a majority of EU member states last year, amid a surge of migration into the EU that saw more than 1 million people reach the continent, with many of them fleeing war and conflict in the Middle East.
Hungary, Slovakia, Romania and the Czech Republic all voted against the plan.
Budapest and Bratislava are both challenging it before the European Court of Justice, the EU's top court.
Hungarian conservative Prime Minister Viktor Orban has been openly hostile to migrants and a vocal critics of the EU quota arrangement, and particularly Germany's "open door" migration policy, after Berlin said last year it would not turn back any Syrian asylum seekers.
"So far nobody has asked the people in Europe whether they accept or reject the mandatory resettlement of migrants," Orban said in February, announcing the plan to hold a referendum.
Hungary was the first EU country to block entry to migrants and refugees, first by erecting a fence along the border with Serbia in September 2015, then by barring passage from Croatia a month later.
Those moves came at the peak of refugee and migrant arrivals along the Balkan route, from Turkey across Greece, Macedonia and Serbia.
The Hungarian fence then diverted the daily flow of thousands of people towards Croatia and Slovenia.
Orban's cabinet has since pushed through harsh laws aiming to discourage migrants from attempting to reach wealthy EU nations by crossing its soil.
"The [migration] route can go any way it wants, but it is certain that it will not go through Hungary," Orban said in January.
Among other things, migrants can now be prosecuted and imprisoned if they enter Hungary by damaging the border fence.
On Tuesday, Hungarian authorities extended the border zone to eight kilometres, expanding the area in which police may expel all migrants they catch without offering them the chance to apply for asylum.
Hungary had one of the EU's highest rates of asylum requests last year. But of the 199,000 applications received in 2015 and 2016, just 264 have been approved.