But Polish Interior Minister Mariusz Błaszczak vowed that Warsaw would not cave in to demands by Brussels, arguing that Islamic migrant communities in Europe increased the threat of terrorism.
“The European Commission has today decided to refer the Czech Republic, Hungary and Poland to the Court of Justice of the EU for non-compliance with their legal obligations on relocation,” the EU’s executive said in a statement.
“Poland has not relocated anyone,” it added.
Błaszczak reacted sharply, saying: "Experience shows that the [migrant] relocation system has not worked. It is a system that poses a threat. It degrades states, entire cities, city districts because the communities that are flowing in to Europe not only do not integrate with Europeans, but ... form a hinterland for Islamic terrorists."
The European Commission launched infringement procedures against Warsaw, Prague and Budapest in June.
Waves of migrants
In September 2015, EU leaders agreed that each country in the bloc would accept a number of migrants over two years to alleviate the pressure on Greece and Italy, which have seen waves of migrants arriving from the Middle East and Africa.
EU leaders agreed to relocate a total of about 160,000 migrants of more than two million people who arrived in Europe since 2015.
Poland’s previous government led by the Civic Platform party agreed to take in over 6,000 people.
But after coming to power in October 2015, Poland's conservative Law and Justice (PiS) government staunchly opposed the arrangement.
Polish Prime Minister Beata Szydło has previously said that Poland was supporting those in need by increasing humanitarian aid to the victims of the war in Syria and by working with aid organisations to rebuild hospitals.
Szydło has said that helping in this way is not only cheaper but more effective, whereas EU migration policy was not putting a stop to additional waves of migrants to Europe.
Szydło also noted that migrants were not interested in staying in Poland but wanted to head for richer countries.
The Luxembourg-based Court of Justice of the European Union can impose high fines on Poland if Brussels asks for them in a further lawsuit. The procedure could take several years, Polish Radio’s IAR news agency reported.