The Greek coast guard has found the bodies of two children off the eastern Aegean island of Kos, which has been a main point of entry for refugees and migrants this year.
Authorities said one of the dead children was aged between 6 and 12 months. The other is thought to be between three and five years old. Their nationalities were not immediately known.
Last week the UN Refugee Agency (UNHCR) said that at least 102 people have died trying to reach Greece by sea this year. At least 3,000 have died in the Mediterranean as a whole.
The UNHCR said on Friday that a total of 396,500 people have entered Greece by sea since January 1, more than 153,000 of them in September. The nine-month 2015 total compares to 43,500 such arrivals in Greece in all of 2014.
Of those who have arrived, 97 percent are from the world's top 10 refugee-producing countries, led by Syria (70 percent), Afghanistan (18 percent) and Iraq (4 percent).