VIENNA, Aug 25, 2011 (AFP) - Austrian police announced Thursday they had arrested an 80-year-old man suspected of sexually abusing his two daughters over more than 40 years, keeping them virtually locked up in his house.

The man was arrested at the prosecutor's request on suspicion of assault, duress, rape, and abuse and neglect of minors or defenceless persons among other offences, Alois Lissl, police chief for Upper Austria told the Austria Press Agency (APA).

The suspect, who was detained as a flight risk, has been sent to a jail in Ried im Innkreis. 

Upper Austria police announced earlier Thursday that the unnamed 80-year-old was suspected of abusing his two daughters, now aged 53 and 45, physically and sexually from 1970 until May 2011.

He also prevented them from having any social contact outside the home and regularly threatened them with weapons and even death, the police said in a statement.

The case reached the authorities in early May after a social worker notified the police.

The man had tried to rape his oldest daughter, who pushed him away and he fell. Unable to stand up or call for help, he was eventually found by the social worker, whom the daughters had called two days later, police said.

For years, the man and his daughters shared just one room of their house in the district of Braunau, near the German border, police added.

Neither the suspect's and victims' names, nor the town where the events happened have been released. 

The two women testified that they had to sleep on a small wooden bench and that their mother -- who died in 2008 -- was also regularly abused by her husband.

"They were evidently locked up in their own house, hardly ventured out into the open," Lissl told Austrian television ORF.

"They received (outside) care but were evidently so intimidated that they kept quiet about these acts their entire life."

"The alleged victims exhibit some mental deficiencies," local police chief Martin Pumberger told APA.

He added the suspect had denied all the accusations against him.

As an interim measure, the man had already been banned from returning to his home for at least six months, according to a prosecution spokesman.

Before his arrest, he was staying in a nursing home in Braunau, after a spell in hospital for treatment after his fall, police spokeswoman Hermine Prokesch also told AFP. 

The case eerily brings to mind an earlier Austrian incest story, that of Josef Fritzl, who locked his daughter in a cellar for 24 years and fathered seven children with her, one of whom died.

Fritzl was sentenced to life in prison in March 2009.