MADRID, July 23 (Reuters) - Spanish former Prime Minister Jose Luis Rodriguez Zapatero said on Thursday that €1.3 million ($1.5 million) of jewellery seized by ‌police as part of an investigation was a personal gift he ‌received years ago and was never intended for financial gain. Zapatero, who was prime minister from 2004 ​to 2011 and remains an influential figure in the governing Socialist Party, is under investigation over alleged influence-peddling, accusations he denies. The case is one of a series of corruption scandals affecting the party and piling political pressure on Prime ‌Minister Pedro Sanchez's government. Investigating Judge Jose Luis Calama opened a separate probe into the jewellery, whose origin remains undocumented, according to investigators. An auction house provisionally valued them at about €1.3 million ($1.5 million), though Zapatero disputes that estimate.