Sarkozy denounced what he called the "political interference" in the case against him on Wednesday in an extract of an interview with LCI television and Europe 1 radio.

"The situation is sufficiently serious to tell the French people we stand where we stand on the political exploitation of part of the legal system today," he said.

Sarkozy denied any wrongdoing.

"I say to all those who are listening or watching that I have never betrayed them and haven't ever committed an act against the Republic's principles and the rule of law," the under-fire former president said.

The 59-year-old said he was "deeply shocked" by the charges against him.

"Everything is being done to give me an image that is not truthful," Sarkozy said.

"In our country, which is the country of human rights and the rule of law, there are things that are being organized," he added. "The French need to know what they are and, in conscience and freedom, judge what to make of it."

Under investigation

Sarkozy spent almost all of Tuesday being questioned by police as part of an investigation linked to allegations that he took 50 million euros ($67 million) in illegal campaign funds from Libya's Moammar Gadhafi. He is also suspected of having used his influence as president to secure leaked details of an inquiry into alleged irregularities in his 2007 election campaign.

The dramatic developments mark the first time a former French head of state has been taken into custody. Sarkozy lost presidential immunity from legal prosecution a month after he left office in June 2012, and if convicted, he faces up to five years in prison and a fine of 500,000 euros.

Phone-tapping

The probe is one of six legal cases involving Sarkozy, directly or indirectly, including allegations of irregularities in his unsuccessful 2012 election campaign.

Last October a court dropped inquiries into whether he had exploited the mental frailty of France's richest woman, L'Oreal heiress Liliane Bettencourt, to fund that campaign.

But as investigators used phone-taps to examine separate allegations that Gadhafi funded the same campaign, a new suspicion arose that he had kept tabs on the Bettencourt case through a network of informants.

Those suspicions finally prompted the formal launching of yet another investigation into influence-peddling in February.

Sarkozy has likened the magistrates behind the phone-tapping to the "Stasi" police of former communist East Germany.

dr/ipj (Reuters, AFP, AP)