Austrian prosecutors say the three-year prison term of a British historian convicted of denying the Nazi Holocaust is too light and have appealed the ruling.

A spokesman for the Vienna prosecutor's office, Walter Geyer, announced the appeal of the sentence of David Irving.

The historian Monday pleaded guilty to charges of denying the Holocaust following his arrest in November over comments he made in 1989.  He told the judge that he had abandoned those views after finding documents by the chief planner of the Jewish genocide, Adolf Eichmann.

The chief judge, however, said he did not believe Irving was sincere.

The British historian also has said he plans to appeal the sentence.

Irving has written books calling Nazi concentration camp gas chambers a hoax, and he has said that Nazi forces killed far fewer than the estimated six million Jews.

Some information for this report was provided by AFP, AP and Reuters.