Officials said Josef Fritzl said nothing on the advice of his lawyer
An Austrian man who admitted holding his daughter in a cellar for 24 years and fathering her seven children has appeared before a regional court.
Josef Fritzl, 73, did not say anything to the magistrate in the court in St Poelten, Lower Austria, and was taken into investigative custody for 14 days.
Police are continuing to search the cellar of his house in Amstetten.
They said Mr Fritzl has also admitted burning the body of a baby that died shortly after being born there.
His daughter Elisabeth, now 42, and her six surviving children have been taken into care.
Reuters news agency said Mr Fritzl appeared calm when he appeared in front of the magistrate at the court in the provincial capital of Lower Austria on Tuesday afternoon.
He said nothing on the advice of his lawyer, officials said, and was remanded in custody at the city's prison.
Questions have been asked as to how Mr Fritzl could keep the cellar a secret
He will be placed in a cell where he can be monitored in case he tries to commit suicide, they added.
Police are still trying to establish how Mr Fritzl concealed the birth of the babies, how he cared for them and how his wife did not know what was going on.
But a lawyer for the victims said the case showed no sign of institutional failure on behalf of the Austrian authorities.
"Up until now there is no sign that there was any mistake by officials," the lawyer, Christoph Herbst, was quoted as saying by the Austrian Press Agency (APA).
"If there had been such a mistake we would obviously have to talk about it."
Photos of Mr Fritzl's basement show a concealed network of tiny windowless chambers which were soundproofed.
Elisabeth Fritzl disappeared aged 18 on 28 August 1984 when, according to her testimony to police, her father lured her into the cellar, drugging and handcuffing her before locking her up.
She is reported to have been made to write a letter which made it look as if she had run away from Amstetten, a small town about 130km (80 miles) west of Vienna.
The head of the criminal affairs bureau in Lower Austria, Franz Polzer, said Mr Fritzl had admitted sexually abusing his daughter repeatedly during the time he imprisoned her.
Mr Polzer said Mr Fritzl had told investigators that Elisabeth had given birth to seven children, including twins in 1996, but one died shortly after being born and that he had thrown the body into an incinerator in the building.
The surviving children are now aged between five and 19 years.
The cellar rooms, covering an area of approximately 60 sq m (650 sq ft), were equipped for sleeping and cooking, and also contained sanitary facilities.
Police said a reinforced concrete door was built into the wall that separated the "dungeon" from the house and was electronically locked. The code was known only to the suspect, who provided his captives with food and necessities.
KEY FACTS IN CASE
Elisabeth reappeared at home after disappearing 24 years ago
Six children she says are hers have been found and placed in care
One of the children, aged 19, is seriously ill in hospital
Elisabeth's father Josef Fritzl, 73, has been arrested on suspicion of incest and abduction
Police say Mr Fritzl confesses to imprisoning Elisabeth and fathering her seven children
Three of the children were kept in the cellar with their mother and had never seen daylight, police told a news conference.
The other three children were adopted or fostered by the suspect, after he forced Elisabeth to write a letter saying she could not look after the baby, according to police.
His wife, Rosemarie, with whom he had seven of their own children, appears to have been unaware of the alleged crimes, police said.
The alleged abuse and Mr Fritzl's apparent double life came to light when the eldest of the children in the cellar, 19-year-old Kerstin, became seriously ill earlier this month and had to be taken to hospital.
Kerstin is said to be in a coma in hospital.
The BBC's Bethany Bell says the case is reminiscent of that of Natascha Kampusch, the Austrian teenager held captive in a cellar in a house in a Vienna suburb for eight years, who ran to freedom in 2006.
On Monday, Ms Kampusch, now 20, issued a statement saying she wanted to contact Elisabeth Fritzl to offer emotional and financial help.
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