Austria summoned Hungary's ambassador on Wednesday after Budapest stopped accepting asylum seekers from other EU states, defying European authorities and potentially swelling the influx of migrants that Vienna must process.
Hungary's government refused to take any more migrants sent there under EU regulations as of Tuesday, demonstrating its frustration with proposals to spread asylum seekers around the continent more equally.
Vienna has asked the European Commission to check if that action violates EU treaties, a foreign ministry spokesman said.
With EU leaders due to debate a new scheme on Thursday to relocate Mediterranean migrants, the Commission has also demanded an immediate explanation from Hungary.
Hungary's refusal to take back refugees would exacerbate neighboring Austria's problems in dealing with an ever increasing influx of migrants.
In Budapest, Hungarian Foreign Minister Peter Szijjarto said the country was fully complying with its EU obligations but was struggling with capacity problems due to a massive flow of illegal migrants from Serbia.
Of plans by Austria and other member states to send illegal immigrants back to Hungary, he said such migrants should be returned to Greece, where they first entered the EU.
