ATHENS — Greece’s coast guard said Friday it has prevented five boats carrying more than 120 people in total from illegally entering Greek waters in the eastern Aegean Sea from Turkey.

A coast guard statement said patrol boats from the European Union’s Frontex border agency helped in the operation, and none of the migrant boats were allowed to reach Greek waters.

It said Turkish coast guard boats eventually arrived at the scene, off the island of Kos, and picked up the migrants.

Greece’s eastern Aegean islands are a major destination for people fleeing conflict or poverty in the Middle East, Africa or Asia who are seeking a better life in the EU. About a million made the crossing during Europe’s migration crisis in 2015.

Under a 2016 agreement with the EU, Turkey — Greece’s historic regional rival — has committed to limit the flows of migrants trying to reach Greek shores. Nevertheless, thousands of people still risk the often dangerous crossing every year, using small unseaworthy boats provided by smuggling rings. Fatal accidents are frequent.

Stronger deterrence by the Greek coast guard and Frontex have substantially reduced the numbers reaching Greece. Nevertheless, Turkish officials and human rights groups have accused Greece of engaging in illegal returns of people who have succeeded in entering its waters or territory. Athens denies the accusations.

Rights groups also accuse Greece of breaching migrants’ rights by not allowing them to enter. Both Greece and Turkey have substantial populations of refugees and migrants.

Also Friday, Greek authorities said they arrested five men — four Syrians and an Algerian — near the northeastern land border with Turkey who had entered the country illegally and were carrying ten handguns with them. The suspects were aged 21-32, officials said.