Reports of the worst ever migrant sea disaster on the Mediterranean — where as many as 850 migrants are thought to have drowned this weekend — had European officials scrambling to address the crisis at what is being called the world’s “deadliest border crossing.”

The boat’s Tunisian captain and a Syrian crew member were arrested on suspicion of human trafficking when they arrived in Sicily — in keeping with strict anti-trafficking laws intended to reduce human smuggling. And European Union officials announced the release of a 10-point plan to tackle the issue. The plan would double the size of the European Union’s border control operation “Triton” and launch a systematic effort to destroy smugglers’ vessels, among several proposals aimed at processing and preventing future migrants. Meanwhile, many in the European Union remain wary of rescue operations, which they say make work easier for smugglers and encourage more migrants to try to reach the continent illegally.

But immigration and human-rights advocates argue that addressing the crisis will require Europe to look beyond its watery border and the people who seek to ferry refugees across it. Blaming search-and-rescue missions, or even the smugglers themselves, for the 220,000 unauthorized migrants who arrived in Europe last year ignores the root of the problem, they say.

“This is an era of unprecedented movement across borders,” said Flavio Di Giacomo, a spokesman for the International Organization of Migration in Italy. “The arrivals at sea are just a small consequence of what’s happening.”

Poverty, political instability and civil war in Africa and the Middle East are powerful “push factors” for migration, Di Giacomo said, regardless of E.U. immigration policies. Syrians, who account for the largest number of arrivals by boat, have escaped a civil war that has killed more than 200,000 and turned nearly 4 million more into refugees. The United Nations expects another 500,000 Syrians to leave the country in 2015, according to the Associated Press. Refugees from Eritrea, the second-largest group of migrants, cite economic issues, forced conscription and a repressive government as their reasons for leaving. Many other Mediterranean migrants are people from sub-Saharan Africa who moved to Libya looking for work but are now seeking to escape violence and instability there.

Francesc Ortega, an economics professor and immigration expert at the City University of New York — Queens College, said that Europe will continue to see unauthorized immigrants crossing the Mediterranean as long as poverty and conflict persist. In a 2013 study, he found that income disparities are a main driver of immigration — more significant than individual immigration policies.

“The migratory pressures to Europe are something that’s not going to go away,” he said in a phone interview. “And the truth is there are very limited legal pathways to migrate to Europe. . . . Those two facts combined make smuggling very profitable.”

Di Giacomo and Ortega both say that unauthorized migration across the Mediterranean won’t change until the “push” factors driving people from the Middle East and North Africa are resolved — hardly an easy task. In the meantime, search-and-rescue missions are the only thing standing between migrants and death at sea, they say.

European officials seemed to recognize that fact this week, when they announced their 10-point plan for dealing with the crisis and a summit of E.U. leaders set for Thursday.

“Now is time for the European Union as such to tackle these tragedies without delay,” Federica Mogherini, the E.U.’s high representative for foreign affairs, said in a statement before the 10-point plan was unveiled. “We need to continue to work on the root causes of migration and most of all on the instability of an area that is broader and broader, from Iraq to Libya.”

But critics said the efforts were too little, too late.

Karl Kopp, a spokesman for the Berlin-based rights group Pro Asyl, called for emergency reception centers in Italy and Greece and other immediate action to aid migrants.

“Considering how dramatic the situation is, this is a joke,” Kopp told The Washington Post. “This 10-point plan does not do justice to the mass dying in any way.”

Since Italy’s “Mare Nostrum” mission — which dedicated five ships, 14 planes and about $9 million per month to scanning 27,000 square miles of ocean for abandoned and wrecked boats — wound down last year, most of Europe’s efforts to deal with the crisis have focused on border control and anti-smuggling measures.

Some officials have argued that rescue efforts wind up encouraging more migrants to come.

British Foreign Office Minister Joyce Anelay spelled out that position in a question-and-answer session in the House of Lords last fall: “We do not support planned search and rescue operations in the Mediterranean,” she said. “We believe that they create an unintended ‘pull factor,’ encouraging more migrants to attempt the dangerous sea crossing and thereby leading to more tragic and unnecessary deaths.”

Last summer Matteo Salvini, leader of Italy’s right wing Northern League party, called the Mare Nostrum program a “taxi service” for migrants, arguing that it just aids the “merchants of death” who profit from human trafficking.

German Interior Minister Thomas de Maiziere echoed some of those concerns, in less dramatic language, on Monday.

“Search and rescue alone is not a silver bullet,” he said. “If you just organize search and rescue, criminals who get the refugees on board will send more boats.”

It’s true that smugglers have come to rely on rescue missions. Some have been known to take their boats halfway out to sea, then abandon them, assuming that the Italian coast guard or a commercial vessel will come to the rescue. Usually the organizers of the trip are not on board the ship at all when it is captured — International Organization of Migration spokesman Leonard Doyle told NPR that boats are often captained by a volunteer who is offered a free passage in exchange for steering the ship.

But Di Giacomo said that limiting rescue missions for the sake of making things more difficult for smugglers is “dangerous” and inaccurate.

“It’s very, very wrong to say that life-saving operation could be a pull factor,” he said.

The numbers speak for themselves, he argued. The number of people attempting to cross the Mediterranean hasn’t decreased since last October, when Italy ended its Mare Nostrum program because of funding pressures and domestic opposition.

The only thing that has changed is the death toll, which jumped from 96 in the first four months of 2014 to well over 1,500 in the same period this year, according to the International Organization of Migration.

The E.U. plan announced Monday also includes measures to track and prevent smuggling, including an operation to destroy smuggling vessels modeled on the “Atalanta” program that countered piracy off the coast of Somalia and an investigation of criminal networks in Libya that organize the voyages.

“We should put the blame squarely with the criminal human traffickers who are the ones managing, promoting and selling this trade, this trade in human life,” British Prime Minister David Cameron told the Guardian. “We are doing everything we can to try and stop them.”

But this argument has gotten backlash from rights groups. Human Rights Watch executive director Kenneth Roth typed several angry tweets this week condemning Europe’s response to the disaster.

And Tugba Barasan, an expert in security and migration at the University of Kent in England, said in a phone call that immigration restrictions and the crackdown on smugglers are part of what turned the migrant crisis into a humanitarian disaster. Instead of deterring migrants, these laws make smuggling operations more profitable, more professional and far more brutal.

“It’s easy to blame smugglers for everything — blaming smugglers is a way to dislocate blame from E.U. and member states,” she said in a phone interview. “I’m not saying that smugglers are not guilty of losing human lives, but the smuggling business has become this way because of all the securitization and criminalization measures.”

“The higher the barriers are the more professionalized the counterparts get and the less these people care about lives lost,” she added.

And indeed, smugglers’ treatment of their passengers has become increasingly brutal, Di Giacomo said. In Libya, refugees are locked in connection houses and often abused by the traffickers. Migrants report being raped or beaten by smugglers — a technique intended to control them, a Doctors Without Borders official told Reuters. But few try to flee, because the streets of Libya’s coastal cities have become as dangerous for foreigners as the buildings where they’re locked up, Di Giacomo said.

“If you are in Libya in this moment you risk your life every single day,” he said.

When they arrive at the beach, the migrants pay their fare and are forced onto crowded, rickety vessels, sometimes at gunpoint. In the case of Sunday’s shipwreck, hundreds of refugees were locked in the hold of the boat — almost ensuring their deaths when the ship capsized.

Those who take such a risk do so because they have no other options.

“These are the most desperate people,” Di Giacomo said. “One man told me: ‘We are between hell and the deep blue sea.'”

Correction: An initial version of this story incorrectly stated that the “Mare Nostrum” program cost $9 billion. The correct number is $9 million.