EU member states today approved a six-month extension of border controls in the passport-free Schengen zone, which were reintroduced in some places in response to the migrant crisis.
The European Council, which represents the 28 EU member states, backed last week's recommendation from the executive European Commmission.
The Commission had received requests for an extension from Germany, Austria, Denmark and Sweden as well as non-EU Norway, which is also a Schengen member.
Since 2015 several countries in the 26-nation Schengen zone have reintroduced border controls due to the worst migrant crisis since World War II -- effectively suspending its principle of open-borders travel.
EU rules say countries in exceptional circumstances can reintroduce border controls for up to two years, in periods of up to six months at a time.
"Austria, Germany, Denmark, Sweden and Norway should maintain proportionate temporary border controls for a maximum period of six months," the council said in a statement announcing the extension.
"Border controls should be targeted and limited in scope, frequency, location and time," it said.
It added such checks should be limited to what is "strictly necessary to respond to the serious threat and to safeguard public policy and internal security resulting from the secondary movements of irregular migrants."
Member states like Germany, Austria, Denmark and Sweden have said the attacks on November 13 in Paris and March 22 in Brussels also "demonstrated that terrorist groups are likely to try and take advantage of deficiencies in border controls."
The extended controls affect the land borders between Austria and three neighbours: Hungary, Slovenia and Germany.
Also affected are Danish ports with ferry links to Germany, the Danish-German land border, some Swedish harbours and the Oeresund bridge, and Norwegian ports with ferry links to Denmark, Germany and Sweden.
The Commission on May 4 said the extension of checks on some Schengen internal borders was justified because the bloc's external border in Greece was still not solid enough despite an EU-Turkey deal that has dramatically reduced the flow of migrants over the Aegean sea.
Greece was the main point where the more than one million asylum seekers -- mainly Syrians, Iraqis and Afghans -- entered Europe last year.
