FEW images of immigrant traffic across the Mediterranean have been as harrowing. Italian TV viewers this week saw the lifeless bodies of 45 African men being lifted, like animal carcasses, from the hold of a fishing boat in which they had tried to reach Europe. Others on the vessel said the men begged to be let out but, for fear of it capsizing, they were forcibly kept below and suffocated.

Around 5,000 people were picked up by patrol boats on June 28th-29th, the busiest weekend of the year so far. On July 2nd another 70 migrants were reported lost at sea in a separate incident. All this comes after Italy began a search-and-rescue effort called Operation Mare Nostrum, in response to the tragedy last October in which 360 people drowned off Lampedusa, an island half-way between Sicily and the North African coast. On July 1st the police arrested five Eritreans who prosecutors said were part of a ring, with bases in Sudan, Libya and Italy, that arranged the latest ill-fated journey. In a wiretapped phone call, one was heard disowning responsibility for their deaths because “it was their fate”.

The latest horrors produced more agonised hand-wringing, but no sign that Italian or European Union leaders are any closer to agreeing what should be done. Mare Nostrum completed a U-turn for a country that until 2011 blocked immigrants at sea, returning many to Libya, their main point of departure. Some Italians believe this policy deterred people from attempting the perilous crossing, whereas Mare Nostrum encourages them. Matteo Salvini, leader of the xenophobic Northern League, said Italy’s prime minister, Matteo Renzi, and his interior minister, Angelino Alfano, were “stained with blood”.

It is true that, since Operation Mare Nostrum began, arrivals in Italy have soared (more than 65,000 so far this year, against around 8,000 in the first half of 2013). But Greece also saw a large rise, of 142%, in the first four months of 2014, as fighting in Syria intensified. The “cruel to be kind” argument for returning migrants has become harder to sustain as Libya lurches from dictatorship to anarchy.

In ever harsher tones, Italian officials have protested that the EU is not helping enough. Mr Alfano has threatened unspecified reprisals if Cecilia Malmstrom, the European commissioner responsible, skips a meeting in Rome to launch Italy’s six-month EU presidency. But the real obstacles to burden-sharing lie not in Brussels but in national capitals. Italian efforts to put immigration at the top of the agenda for last month’s EU summit came to nought.

Italy’s partners argue that they deal with proportionately far more asylum-seekers. In the fourth quarter of 2013 Germany received proportionally three times as many applications as Italy. But none of the others is mounting, for humanitarian reasons, a naval operation comparable to Operation Mare Nostrum. The cost, initially put at €1.5m ($2m) a month, has exploded to €9.5m. As it grows, the Italian government can expect to come under mounting pressure from public opinion to use its EU presidency to force the club to lend it a hand.