Hungary's prime minister is expected to keep migration a key issue on his agenda after low turnout invalidated a referendum against EU refugee quotas but showed nearly unanimous support for the government position among its supporters.
Analysts said Prime Minister Viktor Orban and his Fidesz party will use their voters' aversion to migrants to distract from unpleasant matters like corruption and difficulties in the health sector.
Support in the referendum for Mr Orban's opposition to future EU schemes to relocate asylum seekers within the bloc exceeded 98%, but only 40.4% of eligible voters cast valid ballots - far below the 50%-plus-one vote threshold.
Hungary is also suing the EU to avoid taking in 1,294 asylum seekers from the 160,000 sought to be relocated from Greece and Italy.
Meanwhile, the EU has sealed a deal with Afghanistan to speed the return of Afghans who do not qualify for asylum, just ahead of a donor conference in Brussels for the conflict-torn country.
Under the deal announced on Monday, Afghanistan commits to re-admit citizens not permitted to stay in Europe and supply travel documents for migrants without papers within a month.
The costs for sending people back will be covered by the EU.
In Serbia, the president said the Balkan country will seal its borders to stop migrants if the European Union countries further along the migration route fully block their boundaries against people fleeing war and poverty.
Tomislav Nikolic said Serbia must avoid becoming a dead end from where migrants can no longer move forward. He says that at that point, Serbia "will have to close its border for migrants... because they don't want to be here".
Serbia has been toughening its policies lately after increasing numbers of migrants have entered the country looking for ways to cross into EU members Croatia or Hungary.
Serbia has already stepped up patrols along its borders with Macedonia and Bulgaria to minimise the influx. There are some 6,000 migrants currently in the country.