AMSTERDAM -- A previously unknown letter written by Anne Frank's father soon after he was freed from the Auschwitz Nazi death camp surfaced in the Netherlands on Friday, offering a moving insight into one experience of liberation.


Written from Katowice near Auschwitz in March 1945 to Otto Frank's second cousin, Milly, in Britain, the letter shows Frank had no idea his family had perished and he was alone.


"Of Frau Edith and the children I know nothing. We are separated at our arrival at Birkenau-Auschwitz September 5th," said the letter, published by daily Algemeen Dagblad to mark the 50th anniversary of the murder of 1.5 million camp inmates.


Frank's wife was killed by the hardships of Auschwitz and both his daughters died of typhus in Bergen Belsen camp.


Anne Frank's teenage diary is an account of life in hiding from the occupying Nazis in an Amsterdam house,.


"We were liberated by the Russians on Jan. 27 and it was lucky that at the time being I stayed at the hospital, as this was left by the Germans intact."


"They tried to make me leave with them but I managed to escape and stayed, that was my chance," he wrote.


Otto Frank remarried in 1953 and died aged 91 in 1980 in Basel, Switzerland.