Poland on Wednesday said it will not fulfill its deal with the EU to intake 7,000 refugees from Syria, citing the suicide bombings in Brussels on Tuesday.
Polish Prime Minister Beato Szydlo said Warsaw would close its borders to refugees, including the share of refugees it agreed to accept under the European Union plan.
Poland is the only EU member state to take such a step after the attacks.
"After what happened in Brussels yesterday, it's not possible right now to say that we're OK with accepting any number of migrants at all," Szydlo told a Polish television channel.
Her government had previously been willing to welcome 7,000 refugees, a small number next to the 2.7 million hosted by Turkey over the last five years.
Europe is facing a large influx of refugees, the largest since World War II. Some 1.1 million refugees flooded into the EU last year alone.
"We're forced above all to ensure the security of our fellow citizens," Szydlo said.
EU leaders agreed on a humanitarian deal last September to distribute 120,000 refugees among member states, while the first group of refugees to be sent to Poland were due to arrive late March or early April.
"Our stance is very cautious, which gives rise to major criticism from other countries in what we call the old EU, who hastily agreed to this influx of migrants into Europe," she said.
Szydlo said that “carelessness is the source of the problems we now face.”