Seven migrants have died of apparent hypothermia on a packed wooden boat, the Italian coast guard said Tuesday after rescuing about 280 others off the coast of Lampedusa.

Three people were dead when the coast guard arrived for the rescue in rough waters, and a further four died while being transported to Lampedusa. Most of the migrants were from Egypt and Bangladesh.

Two coast guard boats conducted the rescue while a boat from Italy’s financial police stood by during “an operation made more complex by the rough sea conditions,” the coast guard said.

Italian authorities said the 20-meter (65-foot) boat was in Tunisian waters when the distress call first came in, but that they were unable to locate the boat. It was later found in the Italian search-and-rescue area, the coast guard said.

The NGO Alarm Phone, which forwards rescue calls from smugglers’ boats packed with migrants to authorities, tweeted that it took Italian rescue boats six hours to reach the migrants in distress.

“Their deaths could have been prevented,” the group said.

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Arrivals in Italy this year are significantly higher than the past two winters, totaling 2,051 through early Tuesday, compared with 872 in the same period last year and 835 a year before that. Arrivals typically peak in the summer months.

The International Organization for Migration has marked 2021 as the deadliest for the central Mediterranean crossing route since 2018, with at least 1,315 dead. Bodies aren’t often recovered and the deaths are presumed from the accounts of survivors. More than 23,383 migrants are missing and presumed dead in the Mediterranean since 2014, 80% of those in the central Mediterranean.

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