State-run radio said he had been replaced by Ahmed Midaoui, the former head of national security.

The BBC's Nick Pelham: Few decisions could be taken without Basri's approval

Mr Basri was born in 1938 and had been interior minister since November 1981.

A former police commissioner, he first entered government as long ago as April 1974 as secretary of state for the interior and was the late King Hassan's closest aide.

So far, there has been no explanation for the change.

Sahara problem

Mr Basri ran the system of security force rule which held Morocco, under Hassan II, in check for 20 years.

Driss Basri: No longer the king's right hand man

In that time, he built up immense authority, controlling not just the interior ministry but also communications and the kingdom's local affairs.

From the early 1980s, few decisions could be taken without Mr Basri's approval.

He arranged the country's elections and it was he who both advised Hassan II and implemented his will.

Mr Basri also managed the portfolio of the Western Sahara, the disputed territory in the South which Morocco has controlled for 25 years.

His handling of Western Sahara may have proved his undoing, correspondents say.

Diplomats say recent pro-independence demonstrations in the territory have been brutally suppressed by Mr Basri's forces.

And Morocco's new king, who succeeded his father in July, has emphasised he wants to reign over a state of law not of fear.