At least seven people, including a pregnant woman, have drowned after a boat carrying migrants and refugees capsized 8 kilometers (5 miles) off the Italian island of Lampedusa early Wednesday, officials said.

About 10 other people were missing, Luigi Patronaggio, the chief prosecutor of a team leading investigations into the deaths, told Reuters. The migrants are believed to have started their journey in Tunisia, said Patronaggio, who is working with magistrates based in the Sicilian city of Agrigento.

"This latest tragedy in the Mediterranean is heartbreaking, I wonder what else has to happen to make Italy and Europe understand that we cannot go on like this," Lampedusa's mayor, Toto Martello, said. Coast guard units managed to rescue about 46 other migrants from the 8-meter-long boat after it overturned, and bring them back to Lampedusa, officials said.

Two coast guard ships responded to a distress call from the boat, Italy’s coast guard said in a statement. The statement said that as the rescuers approached, the passengers "suddenly shifted," which likely caused the boat to overturn. Coast guard units rescued about 46 people from the vessel after capsizing, officials said, and brought them back to Lampedusa.

More than 250 more migrants landed on the tiny island overnight on four other ships, local media reported. Arrivals in Italy – one of the main migrant routes into Europe – had been falling in recent years, but numbers picked up again in 2021.

Almost 19,800 migrants have arrived since the beginning of the year – many of them fleeing conflict and poverty in Africa and the Middle East – against just over 6,700 in the same period last year, Interior Ministry figures show.

Lampedusa, which is closer to Africa than to the Italian mainland, is one of the main destinations of Libyan-based human traffickers.