ATHENS, March 28 (Xinhua) -- A rescue operation was underway on Wednesday to locate up to 20 refugees and migrants who were reported missing at Evros River at the land border separating Greece with Turkey, according to Greek national news agency AMNA.

No official announcements have been made yet. But according to AMNA, Greek authorities were alerted after a call received by the European emergency number 112 on late Tuesday.

Weather conditions in the area were adverse on Wednesday. Due to heavy rainfall this week, the level of water in the river has risen above the alert threshold.

Deputy Regional Governor of Evros region Dimitris Petrovic told AMNA that approximately 4.5 hundred hectares are under water and local authorities consider declaring municipalities in the area in a state of emergency.