Leading centre-left newspaper El Pais on Thursday published account ledgers kept by two former treasurers of the party purportedly showing that at least a dozen senior party officials received payments from a secret slush fund.

The report has sparked daily protests by hundreds of demonstrators outside of the right-leaning party’s headquarters in Madrid as well as in other locations across the country at a time when the unemployment rate stands at a record 26 percent.

Sharp drops Monday on stock markets across Europe have been blamed on the political uncertainty in Spain, where the IBEX 35 index was down more than two percent in afternoon trading.

The Popular Party will launch lawsuits against “anyone or any group of people who have accused the Popular Party or its management structure of illegal or irregular actions,” one of the party’s secretaries, Carlos Floriano, told reporters.

The lawsuits will target “all those who leaked” the allegations as well as “those who published them”, he added without specifying who would be cited in any legal action taken by the party.

El Pais said the slush fund used to make the illegal payments was made up of donations, mostly from construction companies.

Ledgers kept by one of the former party treasurers cited by the newspaper, Luis Barcenas, apparently showed payments including 25,200 euros ($34,000) a year to Rajoy between 1997 and 2008.

Barcenas was already under investigation in connection with a separate corruption case, with reports that he had millions of euros in a Swiss bank account.

Rajoy said that case had nothing to do with the party and that it had never had foreign bank accounts.