Tunisian authorities expelled hundreds of sub-Saharan African migrants from the port of Sfax Sunday after they were thrown out of their homes during unrest in July, a rights group said.

"The security forces on Sunday evacuated a square where some 500 migrants were assembled in the centre of Sfax," Romdane Ben Amor, spokesman for the FTDES non-government organisation, told AFP.

He said the migrants were "dispersed in small groups towards rural areas and other towns".

Since Saturday, authorities in Tunisia have been cracking down on illegal migrants, most of whom are from sub-Saharan African countries.

According to authorities, around 200 migrants "who were preparing to make the clandestine boat trip" towards Europe were arrested.

Tunisia is a major gateway for migrants and asylum-seekers attempting perilous sea voyages in hopes of a better life in the European Union.

Racial tensions flared in Tunisia's second city of Sfax after the July 3 killing of a Tunisian man following an altercation with migrants.

Humanitarian sources say that at least 2,000 sub-Saharan Africans were expelled or forcibly transferred by Tunisian security forces to desert regions bordering Libya and Algeria.

Xenophobic attacks targeting black African migrants and students increased after an incendiary speech in February by President Kais Saied.

He alleged that "hordes" of illegal migrants were causing crime and posing a demographic threat to the mainly Arab North African country.

Hundreds of migrants lost their jobs and housing after his remarks.

At least 27 people died and 73 others were listed as missing after being expelled into desert areas bordering Libya in July.