Libya's coast guard has intercepted about 15,000 migrants trying to reach Italy by sea this year, a spokesman said on Thursday, while the United Nations — which gave a much higher estimate — said many were kept in inhumane conditions and subjected to abuse.

The coast guard has stepped up patrols after receiving new boats from Italy as part of efforts by the right-wing government there to stop migrants reaching Italian shores from Africa.

The U.N. Libya mission (UNSMIL) said in a 61-page report on Thursday that the coast guard had intercepted or rescued 29,000 migrants in the first nine months of the year.