Italian Prime Minister Giorgia Meloni's government passed tougher rules to manage irregular migration, amid a surge in the number of migrants.
The move came after almost 10,000 migrants reached the southern Italian island of Lampedusa last week.
Meloni said at the start of a cabinet meeting on the situation that migrants awaiting repatriation should be detained for an initial six months, extendable to up to 18, up from three months now.
"That will be all the time needed not only to make the necessary assessments but also to proceed with the repatriation of those who do not qualify for international protection," Meloni said in her introductory speech.
Government sources said the cabinet approved that measure shortly afterward, as well as the creation of more detention centers in remote areas. Meloni said Italy needed to increase the capacity of such facilities as they had been weakened by "years of immigrationist policies."
Under Italian law, migrants facing repatriation can be held if they cannot be immediately expelled. Officials say a majority of migrants head to Italy for economic reasons and are therefore not eligible for asylum.
In addition, the Defense Ministry will create "structures" to detain migrants who have entered the country irregularly.
These detention centers are to be set up in sparsely populated areas of the country, thereby preventing any "further inconvenience and insecurity in Italian cities," Meloni said.
Past efforts to hold migrants have largely failed, with those detained repeatedly breaking out of centers and often heading straight to wealthier northern European countries.
Meloni visited Lampedusa on Sunday with European Commission President Ursula von der Leyen, who promised a 10-point EU action plan, but the measures resembled previous initiatives that have failed to make much impact.
An agreement struck in July between the EU and Tunisia, from where many of the migrants set sail, has yet to take effect.
Almost 130,000 migrants have arrived in Italy so far this year, according to government data, nearly double the figure for the same period of 2022. The migrants have come from countries including Guinea, Ivory Coast, Tunisia, Egypt, Burkina Faso, Bangladesh and Pakistan.
The government's latest move to stem the migrant flow was condemned by the opposition and rights groups.
The Italian Coalition for Civil Rights and Liberties (CILD) described the detention centers as "black holes" where serious violations of fundamental rights take place, adding that they are expensive and inefficient.
In April, the Italian parliament approved measures to create new migrant centers for people waiting to hear the outcome of asylum applications, as well as more detention facilities for those facing expulsion.
As part of the package, it set aside around 20 million euros ($21.3 million) to fund it over a two-year period.
Sources close to Meloni reported that the prime minister said at the meeting that the government was united behind the decision.
So far this year there are already more than 129,800 new arrivals in Italy, compared to 68,000 at this time a year ago, according to Interior Ministry figures. In 2021, that figure was 43,265, meaning between 2021 and 2023 at this time the number of migrants has tripled.
In recent days, thousands of migrants have again landed on Lampedusa in boats from Africa - last Tuesday alone, more than 5,000 arrived on the island between Sicily and North Africa - a record for a single day.
Thousands were then taken to Sicily or the Italian mainland on ferries and police boats. In the meantime, the situation on Lampedusa has somewhat returned to normal.
But in Sicily, where 1,000 were sent to the southern port city of Porto Empedocle to relieve the overcrowding on Lampedusa, a migrant reception center there was the site of chaotic scenes on Monday, with about a hundred migrants leaving the camp, as they climbed over fences and broke through barriers, according to media reports.
Emergency forces tried unsuccessfully to stop the migrants. The mayor of Porto Empedocle said the migrants were breaking out of the camp because of its poor conditions.
"They did not run away to go to other places, but to look for food and drink," Mayor Calogero Martello told RaiNews.
He called the camp's conditions inhumane and demanded support from the government in Rome.
Porto Empedocle is considered a transit point with migrants coming from overcrowded Lampedusa to be sent to yet other cities after their Sicilian stay.
The camp is currently overcrowded because the transfer to the mainland is proceeding slowly, the Italian news agency ANSA reported.
Back in Rome, Meloni stressed that a tough approach was necessary and she again declared war on smuggling gangs.
"The fight against illegal mass immigration and human traffickers is an epoch-making battle for Italy and for Europe."
The leader of the right-wing nationalist Fratelli d'Italia (Sons of Italy) party has been in power for 11 months. A crackdown on migrants had been among her key promises in the election campaign.
