At least 20 people have died after a migrant boat capsized off the southern Italian island of Lampedusa, a United Nations agency and local media reported on Wednesday.

Rescuers have recovered 20 bodies so far and operations are continuing, according to initial reports by Ansa news agency. Between 70 and 80 people are believed to have survived.

Filippo Ungaro, from the U.N.'s refugee agency UNHCR, expressed "deep anguish" over the disaster and said more migrants could still be missing at sea.

"Deep anguish for the umpteenth shipwreck off the coast of Lampedusa, where UNHCR is now assisting the survivors. It looks to be 20 bodies found and as many missing," Ungaro wrote on social media.

The Italian interior ministry did not immediately respond to a request for comment.

Lampedusa is often referred to as the 'Gate of Europe' due to its geographical location and its role as a primary arrival point for migrants and refugees attempting to reach Europe by sea.