Turkish authorities confirmed on Monday that a second mine, which could have come from Ukraine, was discovered near its coastline, while Romania also said a mine had been found off its Black Sea coast.

Russia had warned more than a week ago that some aged mines that Ukraine had deployed in the Black Sea against its Russian troops had become dislodged from their cables by storms and could drift as far as the Straits of Bosphorus and the Mediterranean Sea. 

The Turkish defense ministry tweeted that "a mine was detected off Igneada near the Bulgarian border" on the Black Sea. 

"The mine has been secured... and an intervention launched to neutralise it," it added. Later, the ministry confirmed the device had been defused.

Another mine found by Romania

For its part, Romanian authorities announced that another mine had been found 39 nautical miles (70-72 km) from the coastal town of Capul Midia. 

According to the defense ministry, the device was spotted by a fishing vessel on Monday morning and was then destroyed by a specialized disposal squad.

On Saturday, a first mine was found and defused by the Turkish navy, after a fisherman had reported seeing it about two kilometers (1.2 miles) off Rumelifeneri, on the entrance of the Bosphorus north of Istanbul. 

Mines floating from Ukrainian waters

Several days ago, Turkish authorities warned on the NAVTEX maritime alert system that there was a risk of mines floating from Ukrainian waters after being dislodged from their anchors by a storm. 

Underwater mines normally have to be equipped with systems that render them harmless if they break free from their anchors. But older mines could lack this safety measure, Turkish media reported.