(CNN) -- At least 22 people have drowned and 10 more are missing after two boats carrying migrants capsized off the Greek island of Samos, a coast guard official said Monday.
Thirty-six survivors have been rescued from the Aegean Sea, and the search is continuing, Katherine Tenta of the Greek coast guard told CNN by phone.
The two vessels foundered about 4 nautical miles off Samos, Tenta said, adding that authorities did not yet know their nationalities.
Thousands of migrants from Africa and the Middle East pack into often unsafe boats to get into the European Union through Greece, Italy, Malta and other coastal states. The numbers have increased since the 2011 Arab Spring uprisings triggered unrest across North Africa and civil war in Syria.
"A 3-year-old child, in a bad condition, has been transferred to a hospital in Athens," Tenta said.
Two search and rescue helicopters -- with help from two coast guard vessels, a navy warship and a cruise liner -- were searching for the missing.
Tenta said the coast guard towed the vessels -- a 10-meter long boat and a smaller vessel -- to Samos. She said 18 bodies were on one: 10 women, five men and three children.
It is not yet clear what caused the boats to capsize, she said.
CNN's Marie-Louise Gumuchian contributed to this report.