In addition to today's protests, Tunisia's Parliament is expected to hold a special session in the coming days to discuss the killing, which critics call an attack on Tunisia's national sovereignty.
Tunisian authorities have arrested 10 people over the shooting of Tunisian aviation engineer Mohammed Alzoari, according to Interior Minister Hedi Medjoub.
The minister told reporters late Monday that Tunisian authorities aren't ruling out Israel's involvement. He said investigators have determined the killing was ordered by two foreigners and plotted from Hungary and Austria.