The Italian coast guard rescued 22 people and recovered nine bodies after a smugglers’ boat capsized in a storm about 30 miles south of the island of Lampedusa, authorities said.

Survivors indicated that the steel-bottom boat had departed from Sfax, Tunisia, overnight on Sunday carrying 46 people from Guinea, Burkina Faso, Mali and the Ivory Coast.

The boat capsized on Wednesday morning as waves reached up to five metres and “the group became very agitated when the engine broke down and they were left adrift”, the UN refugee agency said.

The victims were a six-month-old child and eight men, UNHCR said.

Six of the survivors were treated for severe hypothermia and dehydration, while two remain hospitalised.

After the rescue in rough seas with waves reaching more than two and a half metres, the Coast Guard said it continued air surveillance of the area, which is under Malta’s search-and-rescue area.

Attempts to cross the Mediterranean Sea from Africa to Europe generally increase as summer approaches, raising concerns about more shipwrecks, especially as Italian port rules are restricting operations of charity rescue boats.

Italy’s far-right-led government has recently been instructing charity boats to go to northern ports after each rescue, reducing their operations, and has been impounding boats that it says violates its rules.

“With the arrival of the summer season, we can expect more incidents at sea, as more and more people are leaving with completely unseaworthy metal boats, as we are seeing in these weeks,” said Federico Fossi, a spokesman for the UNHCR in Italy.

The International Organisation for Migration put the number of migrants missing along the deadly central Mediterranean route from northern Africa to Italy at 385 so far this year and 23,109 since they launched the missing migrants project in 2014.