'It's truly a big problem' Mines laid by both sides pose threat in Black Sea

On 11 June, a 50-year-old man entered the calm waters from a beach in the Ukrainian city of Odesa. Every weekend in the summer he had taken a dip to search for sea snails, a local delicacy. But on this occasion he would not return. A mine exploded, killing him instantly as his family watched in horror.

- Lorenzo Tondo

The Black Sea is infested with hundreds of mines dropped by both sides in Russia's war on Ukraine, posing a serious threat to people and the reopening of the grain shipping routes halted by Moscow's sea blockade.

 "It's truly a big problem," said Vladlen Tobak, a former Ukrainian navy diving instructor and the founder of a diving school in Odesa. "These mines are there with other unexploded devices from the second world war, which we continue to find.

"The main concern is that we don't know how many mines were dropped during the naval blockade. It will take a long time to clear the waters of these devices."

Kyiv and Moscow have blamed each other for dropping mines in the Black Sea. The extent of the mining operations remains unknown, but Sergey Bratchuk, a spokesperson for the Odesa regional military administration, said between 400 and 600 mines had been laid by Russia.

In March Russia's defence ministry warned of "floating Ukrainian mines off the coast of Odesa" that had reportedly come adrift after a storm. According to Moscow, the Russian military has mapped out about 370 Ukrainian sea mines.

Sea mines, designed to explode when the hull of a vessel comes into contact with them, are anchored to a steel cable to keep them under water. However, they can come loose in storms and drift long distances in sea currents.