ATHENS (Reuters) - Greece on Thursday rescued 70 migrants at sea, the largest single influx from neighboring Turkey since a failed coup there last month, authorities said.

Refugee and migrant arrivals to Greek islands from Turkey, running into the thousands daily this time a year ago, have largely ebbed after a deal between Ankara and the European Union in March to stem the flow of people, mostly fleeing war and poverty in the Middle East and North Africa.

The Greek coastguard picked up 67 people on board a dinghy off the island of Lesbos, while another three were plucked to safety after falling into the water.

"There was a boat with 70 people on board in distress," a coastguard official told Reuters.

On Wednesday, the Greek coastguard picked up 38 people from a Sierra Leone-flagged vessel in the southern Peloponnese, off the town of Githeon.

Hundreds of thousands of refugees entered Greece by crossing the narrow sea corridor between Lesbos and the Turkish shores last year. Since March, arrivals have fallen sharply.

Greece's Migration Minister Yiannis Mouzalas said on Wednesday the deal with Turkey was largely holding, though Athens was watching developments in the neighboring country with some concern.

Asked what would happen if the deal with Turkey collapses, he told Greece's Skai TV on Thursday: "If we assume the flow resumes, we will be sorely tested. No country is in a position to handle such flows."

Turkish President Tayyip Erdogan vowed on Thursday to choke off businesses linked to the U.S.-based cleric he blames for an attempted coup. The 75-year-old cleric denies the allegations.

(Reporting by Angeliki Koutantou; Writing by Michele Kambas; Editing by Janet Lawrence)