The EU is for the first time sending border guards to help Greece stem an influx of migrants entering across the land border with Turkey.
Many of the illegal migrants claim to be from Afghanistan.
The Rapid Border Intervention Teams set up in 2007 "are activated today for the first time", the European Commission said late on Sunday.
The Commission said the flows of illegal migrants entering Greece had "reached alarming proportions".
Greece requested EU help. The UN says the burden on Greece is "critical".
BBC News
