Petroecuador's public warning to Trafigura follows European Union and United States sanctions imposed on Russian energy supplies after Moscow invaded Ukraine in February. Russia calls its actions in Ukraine "a special military operation."

Petroecuador seeks to stop Russian imports in order to prevent repercussions, including sanctions on Ecuador as well as the country's own officials. The Andean country depends on foreign diesel supplies primarily for motor fuel and electricity.

According to a diesel sales contract awarded in June to Geneva-based Trafigura, the trader was warned to avoid Russian supplies as it delivered 1.68 million barrels of diesel to Petroecuador in six shipments between July and September.

In its statement, Petroecuador noted it already found one shipment contained mostly Russian product.

Trafigura was set to deliver a fourth diesel shipment of around 275,000 barrels on Saturday, 95% of which was of Russian origin with the remaining 5% from Panama, according to the Petroecuador statement. It is unclear what the status of shipment is.

Trafigura said in a statement on Monday that it does not comment on individual shipments but that it is in full compliance with EU sanctions, without going into further detail. It did not address Petroecuador's request to stop importing Russian diesel.

Ecuador's central bank had already warned companies that it cannot issue letters of credit in contracts where Russian oil is involved due to the sanctions.

Petroecuador stressed that it included language prohibiting Russian product imports in the diesel supply contract, worth $256.3 million and covering imports that would allow it to cover diesel demand from the country's electrical, industrial, fishing and oil sectors.