(Recasts with Genena detained for 15 days)
CAIRO, Feb 13 (Reuters) - Egyptian military prosecutors on Tuesday ordered a former anti-corruption chief detained for 15 days for questioning over allegations that he had threatened to publish documents damning the state, the official news agency MENA reported.
Hisham Genena, who had helped to run the election campaign of a potential challenger to President Abdel Fattah al-Sisi in a March election, was taken from his home by police on Tuesday morning to the military prosecutors' office, his family said.
"The military prosecution has decided to detain the former head of the Central Auditing Organization, Judge Hisham Genena, for 15 days for investigation," MENA said.
It said Genena was being investigated over comments he had allegedly made that former military chief-of-staff Sami Anan possessed documents damning the state and its leadership.
Genena had run Anan's short-lived election campaign before Anan was detained last month and accused by the army of running for office without permission, bringing his presidential bid to a halt. Egypt holds its election on March 26-28.
In a statement issued late on Monday evening, the military had said it would pursue all "legal measures" against anyone who tried to harm Egypt's national security.
The statement appeared to refer to an interview Genena gave to the HuffPost Arabi news website, in which he said Anan possessed documents that were damning of senior Egyptian officials, without giving details.
Anan's lawyer criticised Genena, writing on his Facebook page that statements Genena had made were "completely untrue", without specifying which statements he was referring to.
"We will take all necessary legal measures against anyone who makes media statements on Anan's words and actions which harm his legal position," the lawyer Nasser Amin wrote.
Genena's detention came one day after U.S. Secretary of State Rex Tillerson, during a visit to Egypt, called for free and fair elections in the country..
Genena's daughter Nada had earlier told Reuters by telephone that up to 30 policemen had taken her father from the family home in a Cairo suburb. His wife Wafaa Kedieh said he was taken to the military prosecutors.
An Interior Ministry official said he had no knowledge of the incident.
Amnesty International criticised Genena's detention.
"The arbitrary arrest of Hisham Genena and his referral to the Office of the Military Prosecution show a blatant disregard for the rights to freedom of expression and the right to public participation," Amnesty International's North Africa branch said in a message on Twitter.
Genena was beaten up last month shortly after the detention of Anan, and he accused the government of being behind his assault. His alleged assailants said his injuries were the result of a fight after a car accident.
All main challengers to Sisi, who is seeking a second term in the March 26-28 vote, have pulled out of the race, citing intimidation of their supporters and other tactics designed to give the incumbent an easy win.
Egypt says the 2018 presidential election will be free and fair. (Editing by Larry King and Gareth Jones)
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