LISBON (Reuters) - Portugal's former prime minister Jose Socrates, arrested last week on corruption and tax fraud charges, was quoted on Thursday as saying the accusations against him were groundless and that his detention amounted to "gratuitous humiliation".
Socrates' arrest last Friday shocked Portugal. Some analysts say the charges could upset the hopes of his opposition Socialist party, currently ahead in opinion polls, of winning next year's parliamentary election.
His detention was the first involving a former premier in Portugal under democracy and followed other big cases this year as prosecutors and judges intensify a fight against corruption in a country notorious for its slow-moving justice system.
In a letter sent to Publico newspaper and TSF radio through his lawyer, Socrates wrote: "In my legitimate defense, I will rebut the lies told against me and make those who started them answer for them" using the legal system.
"My detention and questioning were an abuse ... The accusations against me are absurd, unfair and unfounded, the decision to put me in preventive custody is unjustified and represents gratuitous humiliation," he wrote.
His lawyer has said he will appeal against his detention. After a three-day interrogation, Socrates was charged on Monday with corruption, tax fraud and money-laundering and ordered to remain in preventive custody.
The crime of corruption carries a prison term of up to eight years.
Portugal's Socialist premier between 2005 and 2011, Socrates said that while he saw the case as having political implications, "it is against me and only me".
He said his Socialist party, which he no longer leads, should not be involved in the process.
It is not clear whether the legal inquiry, named "Operation Marquis", is linked to Socrates' period as prime minister.
During his premiership, Socrates weathered several investigations, including allegations that he misused his post as environment minister in 2002 to allow the construction of a shopping mall. He denied wrongdoing and faced no formal charges.
Socrates resigned as prime minister in the middle of his second four-year term in 2011 as an escalating debt crisis forced him to request an international bailout, which imposed painful austerity measures on Portugal.
(Reporting By Andrei Khalip; Editing by Gareth Jones)