Senegal's privately owned Seneweb news site reported that the authorities had cited “risks of serious disruptions” to public order as the reason for the ban.

The Aar Sunu Election ("Let's Protect Our Election") coalition - which includes civil society, religious and professional groups - called for the protest.

It has not yet made an official announcement on whether or not the demonstration will go ahead.

But the AFP news agency quoted the co-ordinator of the coalition, Malick Diop, as saying that "we will postpone the march because we want to remain within the law".

"The march was banned. There's a problem with the route. So we will change this," he added.

Meanwhile, the communication ministry has announced new internet restrictions to prevent the spread of "hateful messages".

Senegal has been plunged into turmoil since Mr Sall announced on 3 February that elections would be delayed because of a dispute over the eligibility of candidates.

The opposition accused the two-term president of a "constitutional coup", and trying to cling to power.

He has denied the allegation, saying he will not run for a third term.

The election was due to take place on 25 February, but has been pushed back until December.