A German publisher said Tuesday it had canceled the printing of a murder mystery about an honor killing because it contained passages insulting Islam and may have prompted Islamist retaliation.

Droste publishers dropped the book by author Gabriele Brinkmann entitled To Whom Honor is Due after she refused to change several passages, including one where a fictional character is portrayed making abusive remarks about the Koran.

After the Mohammad cartoons, one knows that one can't publish sentences or drawings that defame Islam without expecting a security risk, said Felix Droste, head of Droste publishers.

In 2006, violent protests broke out in several Islamic countries after cartoons of the Prophet Mohammad in a Danish newspaper sparked outrage among Muslims.

The publisher's decision has prompted criticism that it is bowing to Islamist intimidation and curtailing freedom of speech. The firm has also received threats from far-right groups against its employees for being friends of Islamists.

German newspapers ran headlines: Publisher self censors and Fear of Islamist attacks.

The media also compared the decision to an incident in 2006, when a Berlin opera house postponed a production of Mozart's Idomeneo which showed the Prophet Mohammad's severed head, citing security fears.

What on earth is this all about, where are we here? We are in a free country, Brinkmann told German media.

Droste said that while it had a long history of releasing controversial books and was already planning to publish another murder mystery on the topic of honor killing, it would not publish books insulting peoples' faith -- whether Islam, Christianity or other religions.

We do not want to offend religious groups, spokeswoman Nora Tichy said.

Religion