MILAN — The unabated flow of migrants fleeing instability in Libya brought a new horror on Friday: The discovery of 20 migrants adrift at sea who had suffered grave burn injuries in a cooking gas explosion before departing Libya, and then were forced onto a smuggler's boat without treatment.
Italian ships have picked up 10,000 people, many of them refugees of war and persecution, over the past week, an unprecedented number in such a short period. The influx is putting pressure on Italy's shelter system and raising calls for a better response to the emergency.
Friday's rescue comes after the feared drowning of more than 400 migrants in two shipwrecks in the last week, bringing to more than 900 the number of people who have died or gone missing so far this year making the perilous crossing — 10 times higher than over the same period last year.
In Washington, President Barack Obama pledged more intense cooperation with Italy on threats coming from the instability in Libya, which has contributed to the influx of migrants across the Mediterranean. Libya, the closest point in north Africa to Italy, is a transit point for migrants hoping to reach Europe by sea.
Speaking after a meeting with the visiting Italian prime minister, Obama promised to "work together even more intensively to encourage cooperation on threats coming from Libya, including the growing ISIL presence there, as well as additional coordination with other partners in how we can stabilize what has become a very deadly and difficult situation."
Italian Premier Matteo Renzi said he expected to see results of the commitment in the coming weeks. "It has to do with the justice and the dignity of mankind," he said.
Among the burn victims rescued Friday after two days adrift on a half-deflated dinghy was a 6-month-old baby. They were among 70 migrants who were rescued and transported to the Italian island of Lampedusa. One of the burn victims, a woman, died en route.
The U.N. refugee agency said the cooking gas explosion occurred at a holding center run by smugglers who demand thousands of euros (dollars) for a place on unseaworthy boats making the journey across the Mediterranean.
"A gas cylinder exploded and killed several people and injured many others," said the U.N. High Commissioner for Refugees spokeswoman in Italy, Barbara Molinario. "The traffickers would not allow them to leave and reach the hospital so they did not get treatment for a few days. And then they were put on a boat."
UNHCR released video images of the badly burned victims being taken from an Italian vessel after arriving in Lampedusa, a small island off the coast of Sicily. Aid workers helped some whose hands were covered in gauze walk off the boat, while more gravely injured victims were moved by stretcher. Five of the most seriously burned were flown to hospitals in nearby Sicily.
"This latest horrific incident involving human smugglers shows the urgent need to create safe legal alternatives so that refugees don't need to put their lives at risk in this way," the UNHCR said in a statement.
Prosecutors in Sicily, meanwhile, were investigating 15 Muslim migrants for allegedly throwing 12 Christian migrants overboard in a religious dispute. Survivors, who police said resisted being thrown overboard in part by holding on to each other, reported the incident after being rescued.
The Organization for International Migration said the rate of migrant and refugee deaths this year is 10 times higher than in 2014, even though the number of those who made it across safely is about the same. The agency put arrivals so far this year in Italy through Thursday at 21,191. That compares with 26,644 for the first four months of last year.
"This is unacceptable," said Federico Soda, director of the IOM coordination office for the Mediterranean, calling for more intensive search and rescue efforts. "This is a humanitarian emergency that involves us all."
Greece, the EU's second-biggest gateway for migrants after Italy, appealed to its European Union partners Friday for more help in policing its sea borders as immigrants increasingly make dangerous journeys to escape war and poverty in the Middle East and Africa.
The deteriorating security situation in Libya has added new urgency to the migrant crisis. Earlier Friday, gunmen seized an Italian fishing boat with seven crewmembers from international waters and were towing it to the Libyan port of Misrata before the Italian navy intervened and regained control of the boat. There were no immediate reports of injuries. Sicily's main fishing consortium said the seizure appeared related to a dispute over fishing rights.
Fighting in Libya has escalated to its worst levels since the 2011 civil war that ended with the overthrow and killing of longtime dictator Moammar Gadhafi. Rebel groups that fought against him kept their weapons and militias mushroomed in number.
The country now has rival governments, an internationally recognized one in the eastern city of Tobruk and an Islamist-backed one in the capital, Tripoli. The two sides have been negotiating in Morocco to end the fighting.
Associated Press writers Nicholas Paphitis in Athens and Brian Rohan in Cairo contributed to this report.