Hungarian authorities detained seven Ukrainian citizens and seized armored vehicles carrying about $80 million in cash and gold while they were transporting funds from Austria to Ukraine for the state-owned Oschadbank.

The Ukrainians were later released and returned home, but Hungary kept the money, prompting Ukraine to accuse the Hungarian government of illegally confiscating it.

Ukrainian officials say the transfer was a routine bank operation with proper documentation.

The incident has intensified tensions between the two countries amid a dispute over disrupted Russian oil supplies through the Druzhba pipeline, WRAL News has reported.

Hungary’s government has blamed Ukraine for the oil disruption and threatened further measures while political tensions rise ahead of Hungarian elections.