The former director of the International Monetary Fund (IMF), Rodrigo Rato, who was sentenced to four years in prison for embezzlement and fraud, began serving his jail sentence on Thursday.

The 69-year-old arrived alone at the Soto del Real prison with two large suitcases. Spanish prosecutors on Wednesday denied his petition to postpone serving the sentence until after Spain's constitutional court had issued a decision on his appeal.

In February 2017, Rato was found guilty alongside 63 other defendants of fraud and embezzlement at Spanish bank Bankia while he was its director. Bankia was later bailed out by the Spanish government.

The Spanish Supreme Court upheld the ruling against Rato last month.

Although he has appealed the ruling at the country's constitutional court, Rato told journalists in front of prison on Thursday: ‘I accept my responsibilities towards society and admit to my mistakes.’ He also asked for forgiveness.

Rato was the director of the IMF between 2004 and 2007, and was the head of Bankia until 2012. Spanish prosecutors found that Rato and several other high-level officials at Bankia - which in 2012 needed a 20-billion-euro bailout (22.8 billion dollars) from Madrid - had paid their own private bills with credit cards linked to the bank's funds.

Rato is also being investigated on charges of money laundering and tax evasion, and is yet to go on trial for investor fraud and falsifying accounts in relation to the listing of Bankia in 2011.