Rights groups are criticizing the detention of an Omani journalist who is apparently held over an article he wrote regarding improper interference in a court case.

The New York-based Committee to Protect Journalists issued a statement early on Wednesday calling for the release of Ibrahim al-Maamari, editor-in-chief of the daily Arabic newspaper Azamn. The advocacy group says al-Maamari is being investigated on allegations of publishing "false news."

The newspaper published a blank space on its front page this week to protest al-Maamari's detention.

The Gulf Center for Human Rights says al-Maamari previously was sentenced to five months in prison in September 2011 over another article that saw the newspaper shuttered for a month. It also called for his release.

Authorities in the sultanate could not be immediately reached for comment.