The European Commission threatened Italy with legal action on Wednesday for possible breaches of the EU's rules on granting asylum, over its treatment of migrants arriving from Africa on the island of Lampedusa.
A video showing migrants standing naked in the cold while being sprayed for scabies at a detention centre stirred outrage in Italy on Tuesday.
Hundreds of people have died in recent months as refugees seek to enter the European Union by boat through Lampedusa, an Italian island south of Sicily, putting the EU's migration policies in the spotlight.
EU leaders are due to discuss migration at a summit in Brussels on Thursday and Friday, in response to the high number of migrants drowning in recent months.
''The images we have seen from the detention centre in Lampedusa are appalling and unacceptable' - EU home affairs chief, Cecilia Malmstrom
The European Commission's home affairs chief, Cecilia Malmstrom, said the EU executive was investigating Italian
practices in detention centres.
"The images we have seen from the detention centre in Lampedusa are appalling and unacceptable," she said. "We will
not hesitate to launch an infringement procedure to make sure EU standards and obligations are fully respected."
The Commission could take Italy, which bears the brunt of illegal immigration from North Africa, to court over its
adherence to EU rules on acceptable conditions in detention centres, among other issues, officials said.
At the summit later this week, EU leaders will weigh proposals by the Commission to address the issue, including
possible changes in asylum rules that would allow people to ask for protection before actually reaching European soil.
That could make it easier for them to seek asylum.
The Commision has also called on EU governments to give more support to the bloc's Frontex border agency.
Much of the debate within the bloc centres on whether it would be better to focus border control efforts on rescuing
migrants from the Mediterranean or on strengthening preventive measures and cooperation with countries in North Africa.
Some EU countries, including Denmark, Luxembourg, Greece and Spain, have cautioned that boosting EU search and rescue operations could persuade more migrants to attempt the dangerous crossing through the Mediterranean.
Southern EU states including Italy have asked for what they see as a fairer spread of the burden of dealing with migrants and more EU funding, but the bloc is divided on how to deal with the problem. Northern EU states argue they already grant asylum to more people than their southern neighbours.
More than 7,000 migrants may have perished at sea or while crossing deserts trying to reach a safe haven this year,
believed to be the deadliest on record, the International Organisation for Migration (IOM) said.