Monday was a dark day for migrants in the Mediterranean. As the search continued for survivors of the weekend's capsizing off the coast of Libya - from which 800 have been confirmed dead - three separate vessels got into trouble.

Coast guard boats spent the day criss-crossing the sea responding to two boats off the coast of Libya, with hundreds aboard each, and a third that had run aground off the island of Rhodes.

See also: The Deadly Mediterranean Crossing That Migrants Risk Every Day

Amid what Italian Premier Matteo Renzi called an "escalation in these death voyages" two arrests have been made. The Tunisian captain and a member of the crew from the boat that capsized Sunday have been charged with favouring illegal immigration, and the captain also faces the charge of reckless multiple homicide.

They were arrested aboard the rescue boat that brought 27 survivors from the shipwreck to Sicily, the Associated Press reports.

Their human cargo, according to Carlotta Sami, of the United Nations High Commissioner for Refugees in Italy, included Syrians, Eritreans and Somalians, a number of which were children aged between 10 and 12.

A survivor of the boat that overturned off the coast of Libya Saturda, disembarks from Italian Coast Guard ship Bruno Gregoretti, at Catania Harbor, Italy. Image: Alessandra Tarantino/Associated Press

Details of the disaster are beginning to emerge, and Italian prosecutors say that hundreds of migrants were locked below deck unable to escape when the rickety boat capsized off the coast of Libya.

Speaking at a news conference in Catania, Sicily, prosecutor Giovanni Salvi said "a few hundred were forced into the hold and they were locked in and prevented from coming out." He said hundreds more were locked on a second level of the boat, which also had hundreds of migrants squeezed into its upper deck.

The sheer scale of this week's events, with as many as 1,300 deaths in the past week alone, have seen onlookers rush to contextualise the numbers and have prompted what many see as overdue action from the EU.

Equivalent of 5 passenger planes full of people have drowned last week alone http://t.co/VFSGx6XFAe #DontLetThemDrown pic.twitter.com/bEIE2mpJIh — Amnesty UK (@AmnestyUK) April 20, 2015

Joseph Muscat, the Maltese prime minister, called the latest tragedy "a game-changer," and said that "if Europe doesn't work together, history will judge it very badly."

The European Union foreign affairs chief, Federica Mogherini, said this weekend's appalling human toll — which, if verified, would be the deadliest migrant tragedy ever — had "finally" fully awakened the European Union to the evils of human trafficking.

He said that a 10-point package to deal with the crisis that was set out during talks in Luxembourg Monday was a "strong reaction from the EU to the tragedies" and "shows a new sense of urgency and political will."

"We are developing a truly European sense of solidarity in fighting human trafficking - finally so."

The global response

EU interior and foreign ministers decided Monday to launch military operations against the networks of smugglers in Libya, boost maritime patrols in the Med and broaden the search-and-rescue effort. Frontex, which runs the EU's Mediterranean rescue service Triton, will receive more money and its operational area will increase.

Their 10-point plan includes a proposal to take "civil-military" action modelled on Europe's anti-piracy operation off the coast of Somalia, to capture and destroy boats used by traffickers.

The ministers also agreed to work with Libya's neighbours, including Egypt, Tunisia and Niger, to close down migratory routes. A summit in Brussels on Thursday will see them hammer out the details.

The UK's former Liberal Democrat leader Paddy Ashdown has suggested the possibility of using of armed force to destroy boats before they leave Libya.

Australia's prime minister Tony Abbott, meanwhile, called the crisis a "terrible tragedy” and urged European leaders to operate a policy of turning away migrant boats, a tough border control stance currently in existence in Australia.

“The only way you can stop the deaths is to stop the people smuggling trade," he said. "The only way you can stop the deaths is, in fact, to stop the boats."

Cracking down on the human traffickers

Italian Premier Matteo Renzi urged Europe to put the focus on preventing more boats from leaving Libya, the source of 90% of migrant traffic to Italy.

"We are facing an organized criminal activity that is making lots of money, but above all ruining many lives," he said at a joint news conference with Malta's prime minister, Joseph Muscat. He compared their activity to that of slave traders of centuries past, "unscrupulous men who traded human lives."

Renzi said that recent events had proven that providing rescue wasn't always possible, given the conditions of the smugglers' boats and the delicacy of such operations, and that the focus needs to be on preventing the boats from leaving Libya. "Continuing to think that allowing them to depart and then chasing after them means putting at risk human lives," he said.

Italian Premier Matteo Renzi, right, and Maltese Premier Joseph Muscat, hold a joint press conference after a meeting in Rome, Italy, 20 April 2015. Image: Maurizio Brambatti/ANSA via AP/Associated Press

Renzi said the instability in Libya was giving free reign to the traffickers, as evidenced by the escalating migrant flows, but he ruled out sending ground troops to Libya or a naval blockade of migrants, saying that would only provide a corridor for them.

Libya is a transit point for migrants fleeing conflict, repression and poverty in countries such as Eritrea, Niger, Syria, Iraq and Somalia, with increased instability there and improving weather prompting more people to attempt the dangerous crossing.

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.

Malta and Italy are closest to the Libyan coast and have received the brunt of a migrant tide that carried 219,000 people from Africa to Europe last year. Some 3,500 died or went missing along the way, the U.N. High Commissioner for Refugees Antonio Guterres said in a statement Sunday.

The Associated Press contributed reporting.