Ahmed Reda Benchemsi, editor of Tel Quel (As It Is) and its sister publication Nichane (Forthright), was called for questioning by Casablanca police late on Saturday under orders from the judiciary, the Interior Ministry said in a statement.

A reporter at Nichane, who asked not to be named, said Benchemsi had questioned the usefulness of parliamentary elections next month in a country where the monarchy wields ultimate power.

In his annual speech to the nation on July 30, the king said he hoped the September 7 polls would reinforce democracy, and he would oppose anyone who questioned their validity.

The ministry said Nichane had also published articles questioning the Prophet Mohammad and damaging public morals and good manners.

"The prime minister expresses ... his profound indignation at these lapses, which are against the law, the moralisation of public life and the restructuring of the media landscape ...," the prime minister's office said.

The reporter said Benchemsi had been released by police and was back at home on Sunday morning. It was not clear whether he was still being investigated.

It was the second time in a year that the authorities had seized Nichane, a weekly magazine rare for being written in Morocco's local Derija dialect and which regularly takes government officials to task and tests the limits of free speech.

Its former editor, Driss Ksikes, stepped down after it was banned for two months for publishing popular jokes about Islam, sex and politics.

He and a reporter on the publication were both given suspended three-year jail terms.

Morocco's press is widely seen as freer than others in the Arab world but red lines remain which, when overstepped, can land journalists before a judge.

Criticising the king, questioning his role as guardian of Islam and casting doubt on Morocco's claim to the disputed territory of Western Sahara can all lead to a spell in prison.