Youth from Mali's Arab community have brought the ancient city of Timbuktu to a standstill in a protest against the worsening security situation in the region, Reuters news agency reports.

The protesters - many of whom were traders - fired shots in the air, burnt tyres and torched vehicles, it reports.

Mali is due to hold presidential elections on Sunday, but the north of the country is unstable.

UN and government forces have been battling to end an insurgency by militant Islamists.

Tuareg separatists - who were once in an alliance with the militants - are also demanding greater autonomy for the north.