A child has drowned and a Syrian migrant has reportedly been killed on Greece’s border with Turkey – the first deaths since Ankara decided last week to flood the frontier with refugees.

The child, a young boy, drowned after a smugglers’ boat that was taking him and dozens of other refugees from the Turkish coast capsized off the island of Lesbos.

The deaths come as tens of thousands of refugees and migrants tried to enter Greece, either by boat towards its northern Aegean islands or by crossing a land border in the far-north east of the country.

The Greek army said it would conduct military exercises along the land border on Monday, with soldiers using live ammunition.

The 24-hour exercises were due to take place close to two border posts, according to Greek media, citing an announcement by the Fourth Army Corps.

The child was one of two who were found unconscious after the boat capsized. One of them was revived and taken to hospital but the boy died, according to Greek authorities.

The Greek coast guard said the boat had been deliberately capsized so that it could not be turned back to Turkish waters.