The official said some volumes of crude oil had been rerouted to the Baku-Tbilisi-Ceyhan pipeline and to the Caspian Pipeline Consortium this year, while some fuel oil had been sent to the port of Taman in Russia and Georgia's other Black Sea port of Kulevi.

January-May shipments of crude oil and refined oil products from Batumi totalled 495,184 tonnes, down from 1.022 million tonnes in the same period last year, said the official, who asked not to be identified.

In May alone, overall shipments were 79,571 tonnes, compared with 115,086 tonnes the previous month and 104,066 tonnes in May last year.

There were no shipments of crude oil, jet fuel, naphtha, vacuum gasoil and LPG last month.

Shipments of crude oil and refined oil products from Batumi totalled 2.109 million tonnes in 2017, down from 3.377 million in 2016.

Crude and refined oil products from Azerbaijan, Kazakhstan and Turkmenistan are shipped out of Georgia's Black Sea ports of Batumi, Supsa, Poti and a terminal in Kulevi.

Some products are transported across the Caspian Sea in small tankers, unloaded in the Azeri port of Baku and then sent by rail to Georgian ports for export to the Mediterranean.