At least four people were killed when a boat with illegal migrants capsized in the Aegean Sea in western Turkey.According to officials, the incident occurred Saturday off the coast of Ayvalik town, Xinhua reported.The boat carried eight Afghans and was headed towards Greece.Four migrants are still missing, officials said.One helicopter, a plane and a team of pers have been dispatched to the scene as rescue efforts continued.On Monday, a boat carrying 43 Afghan illegal migrants sank off the north-west coast of Istanbul, killing at least 26 people while 11 went missing and six were rescued.