MOSCOW (Reuters) - Japan's Inpex for the first time last month supplied crude oil from its share in the giant Kashagan oil field in Kazakhstan to a German refinery via Russia's Druzhba pipeline, three sources familiar with the shipment and export data told Reuters on Thursday.

"It was a trial supply of oil from Kashagan in April, no supplies (are) planned in May", one of the sources familiar with the plans said.

The shipment - to the Schwedt refinery - shows how Kazakhstan is developing oil exports via the Druzhba pipeline, which connects Russian oil fields to Europe and which otherwise would be empty due to the European Union embargo on Russian crude.

Kazakhstan doesn't have direct access to international sea routes and the lion's share of its oil exports pass through Russian territory. Druzhba's northern leg crosses Belarus and goes to Poland and Germany.

Kazakhstan has been supplying oil to Germany since 2023 via Druzhba as the EU embargo doesn't forbid the purchase of non-Russian oil supplied via Russian pipelines. But up to now, this has mostly been done by Kazakhstan oil producer Karachaganak Petroleum Operating (KPO), in which Eni and Shell are the largest shareholders.

Another source added that the Inpex shipment went well and more supplies from Kashagan to Germany are being considered this year by the Japanese company and other shareholders, but the counterparts need to agree on the details of such supplies.

Inpex declined to comment on the matter due to confidentiality obligations.

Kashagan's operator, the North Caspian Operating Company (NCOC), and the Kazakh Energy Ministry did not immediately respond to a request for comment.

NCOC is a consortium that includes Shell, Eni, TotalEnergies, and Exxon Mobil Corp, as well as Inpex, Kazmunaigaz, and China Petroleum Oil Corp.

NCOC shareholders have been looking for additional export routes as alternatives to Kazakhstan's main export outlet - the Caspian Pipeline Consortium (CPC) - after multiple stoppages of exports via the pipeline in 2022.

Kazakhstan's oil supplies to Germany have recently been challenged by a technical issue between Russia's Transneft pipeline operator and Poland's PERN, putting shipments at risk, but the matter has been resolved.