MADRID -- Spain's prime minister said Wednesday that he is "disturbed" by the financial scandal surrounding former King Juan Carlos I that is being investigated both in Spain and Switzerland.

"We are witnesses to unsettling revelations that have disturbed all of us," Pedro Sanchez said when asked about the court investigation into whether the former monarch received millions of euros in possible kick-backs from Saudi Arabia during the construction of a railway by a Spanish consortium.

Spain's Supreme Court opened the probe last month. Since then, Spanish media outlets have published damaging testimony from a separate Swiss investigation into the same millions that were allegedly given to Juan Carlos by Saudi Arabia's late King Abdullah. Juan Carlos allegedly then transferred a large quantity to a former companion in what investigators are considering as a possible attempt to hide the money from authorities.

The 82-year-old Juan Carlos is credited with helping Spain peacefully restore democracy after the death of dictator Francisco Franco 1975. But marred by scandals in the later years of his reign, Juan Carlos abdicated in favour of his son Felipe VI in 2014, losing his inviolability protection granted by Spain's constitution to the head of state.

After media reports said that Felipe was a beneficiary of the off-shore account holding the alleged 65 million euro gift from Saudi Arabia given to Juan Carlos, Felipe renounced any future personal inheritance he could receive from the former king. Felipe also stripped his father of his annual stipend of 194,232 euros.

The royal house has denied that Felipe had any knowledge of his father's alleged financial irregularities.

Sanchez added on Wednesday that he was pleased by the response of Spain's democratic institutions during the scandal.

"We have reached important conclusions: First, there are media outlets that don't look the other way; second, the justice system works; and third, the royal house has distanced itself from these disturbing revelations," the head of government said.