Opposition leader Pablo Casado criticized the Spanish government for putting the country at risk of U.S. sanctions for its engagement with Venezuela.

In the only televised debate before Sunday’s election, Casado, who leads the second-placed People’s Party, used the threat of sanctions to attack acting Prime Minister Pedro Sanchez.

“I feel ashamed when the U.S. is planning to sanction Spain for its cooperation with a dictatorial regime,” Casado said, calling on Sanchez to do more to seize the assets of former Venezuelan officials in Spain.

Officials in the U.S. Treasury have been pushing for the Trump administration to impose sanctions on Spain for what they say is its financial support for the regime in Caracas, but they’ve run into opposition from the State Department. A spokesman for the U.S. embassy Madrid last week said there is currently no discussion about sanctions and the Spanish government has insisted there is no risk.