At least five illegal immigrants, including three children, drowned off the coast of Lesvos on Thursday in the worst incident of the sort in Greek waters in 10 months, while over 100 people were arrested over the past two days for illegally entering Greece.

In a joint, pre-dawn operation off Nea Mystegna, on the eastern Aegean island’s northeastern coast, coast guard patrol boats, a navy torpedo boat and a rescue helicopter, assisted by local fishing boats, found and pulled 33 people from the water. The bodies of three children, a man and a woman were also recovered. The names or nationalities of the dead or survivors were not made public.

The search followed a phone call from a man claiming to be an Afghan national who said a boat crammed with illegal immigrants that had sailed from Turkey had suffered engine trouble off Lesvos.

It was the worst accident involving illegal immigrants since October 2002, when at least nine Afghan nationals died off Lesvos.

On Wednesday, Turkish police had discovered the drowned bodies of five illegal immigrants on the country’s western coast.

Yesterday, 39 illegal immigrants from Africa and Asia were found on the eastern Aegean islet of Farmakonissi, while Lesvos coast guards arrested seven illegal immigrants from Afghanistan in the vicinity of the island’s airport. Late on Wednesday, coast guards on Lesvos discovered 10 illegal immigrants from Iran and Iraq and two Turkish people-smugglers aboard a speedboat off the coast of Nees Kydonies. And on Rhodes, a group of 29 illegal immigrants — including three women and three children — was found on a beach on the outskirts of Rhodes town on Thursday.