The Tirana prosecutor's office says it has started an investigation into money that Albania's main opposition center-right Democratic Party has used for lobbying in the United States.

A statement received Thursday said that prosecutors have asked the Democrats and the Central Election Commission to explain and show whether an allegedly informal payment of $675,000 (€570,000) through offshore-registered companies has been declared by the party.

Media have reported that in the spring, ahead of Albania's June parliamentary election, the opposition Democrats paid three lobbying companies in the United States to secure meetings and raise their voice with President Donald Trump's administration.

The Democrats suffered a landslide loss at the June vote, securing only 43 seats in the 140-seat parliament.