International campaign group Human Rights Watch (HRW) has accused Tunisian security agents of committing "serious abuses" against black African migrants attempting to get to Europe.

The campaign group said it had interviewed more than 20 migrants and asylum seekers since March.

Seven were among more than 1,000 black Africans expelled or forcibly transferred by the Tunisian authorities to the country's desert border regions with Libya and Algeria this month.

President Kais Saied has accused the migrants of violence and changing the country's demographic make-up.

HRW wants the European Union to withhold funding that was to be used to return the migrants home.