THESSALONIKI, Greece — Greek authorities say they are searching for a group of migrants who made an emergency call saying they were in danger while crossing a river marking the border between Greece and Turkey.

Police and fire department officials said Wednesday an unidentified person called an emergency number Tuesday afternoon saying they were among a group of 15 people trying to cross the Evros river, which was swollen by heavy rainfall. Rescue crews have been searching the area near the Greek village of Praki but had found nothing by Wednesday morning.

Hundreds of people attempt to cross from Greece to Turkey each week. Most make the crossing from the Turkish coast to nearby Greek islands, but many also attempt to cross the river, on the land section of the Greek-Turkish border.