His arrest came after his whereabouts was widely publicised at the weekend, drawing anti-Nazi protesters and journalists to the Budapest apartment where he had lived undetected for 17 years.
The Simon Wiesenthal Centre, a Nazi-hunting rights group, ranks Csatary as the most wanted war crimes suspect still alive.
He is accused of deporting thousands of Jews to death camps while serving as chief of police in the Hungarian city of Kassa (now Kosice in Slovakia), from 1941 until 1944.
However, prosecutors yesterday played down the chances of an early trial.
"The investigation has to explore an event which is remote both in time and place," they said in a statement. "It took place 68 years ago in an area that now falls under the jurisdiction of another country, which raises several investigative and legal problems."
They added that the investigation was dedicated to "finding living victims who might speak directly about events".
Csatary was sentenced to death in absentia by a Czechoslovakian court in 1948. But by then he had escaped to Canada. He worked as an art dealer in Montreal and Toronto until he was unmasked by war crimes investigators in 1995. He then fled back to his native Hungary.
He had been living in Budapest for 17 years when he was discovered last weekend after a tip-off by the Wiesenthal Centre.
Officially, Csatary has been under investigation by the Hungarian authorities since last September and he is reported to have been under police surveillance since April.
The Wiesenthal Centre, which tipped off the Hungarian authorities last October, said it had been hugely irritated by their failure to arrest Csatary sooner.
Ephraim Zuroff, the organisation's chief Nazi-hunter, said he was "very upset and frustrated" by their inaction.
Csatary is alleged to have been renowned for his brutality when he was a police chief in charge of the Kosice Jewish ghetto.
One survivor told investigators after the war: "He beat whoever he found there with a dog whip. On one occasion he ordered every young girl to come and dig out thick wooden stakes from the ground with their bare hands. Even the SS were scandalised by this."
Hungary's apparent reluctance to arrest Csatary has fuelled criticism of Viktor Orban's right-wing populist government, which is widely accused of taking a sympathetic attitude towards World War II fascists and anti-Semites.
Last year a Budapest court's decision to acquit Sandor Kepiro, a 97-year-old Hungarian, on charges of ordering the execution of Jews and Serbs in Serbia in 1942 , was condemned by the Wiesenthal Centre as an "outrageous miscarriage of justice".
In recent months, the Hungarian authorities have rehabilitated the country's wartime dictator, Miklos Horthy, who promoted the works of anti-Semitic writers in schools.
These included Jozsef Nyiro, a supporter of Hungary's fascist Arrow Cross regime, installed by the Nazis in 1944.
- Independent
