A Spanish magistrate investigating former International Monetary Fund chief Rodrigo Rato for alleged tax fraud has frozen 18 million euros ($20.3 million) of his assets plus his IMF pension.

A court statement says the investigating judge ordered the asset freezes on Thursday after Rato failed to deposit money for possible penalty payments.

It didn't specify how much Rato receives for his pension.

Rato headed the IMF from 2004-2007. He was a leading figure within the governing Popular Party who served as economy minister under ex-Prime Minister Jose Maria Aznar between 1996 and 2004.

Rato resigned as chief executive of the Bankia bank in 2012 amid concerns over the bank's solvency during Spain's financial crisis. The bank subsequently received a bailout.

He faces several investigations and has denied wrongdoing.