Ukrainian border guards last week closed several shipping lanes at the mouth of the Danube River due to drifting mines in Black Sea, analyst APK-Inform said on Monday.

Ukrainian Danube ports of Izmail and Reni last week remained the only sea routes for Ukrainian grain exports after seaports were blocked due to the Russian invasion.

Ukraine, a major agricultural producer, used to export most of its goods through seaports but since Russia’s invasion in February has been forced to export by train via its western border or via its small Danube River ports.

APK-Inform said that the traffic along the Danube was significantly limited “because of the danger of blowing up ships on laid in the Black Sea by Russian troops.”

Ukraine has previously accused the Russian Federation of mining shipping lanes in the Black Sea, which makes it impossible for ships to pass in the north western part of the Black Sea. 

The guard is unavailable for immediate comments. 

“Only ports in the Ukrainian waters of the Danube region were fully operated. But they have rather limited bandwidth, leading to accumulation of transport on suitable roads,” APK-Inform consultancy said in a report.

Ukrainian agriculture and transport officials have said the country is seeking to boost export capacity of Danube River ports which allow to ship grain through Danube to Romanian Black Sea ports.

The government gave no data on grain exports through the Danube ports.