The United Nation's refugee agency says the bodies of 26 migrants who apparently drowned have arrived at the Italian port of Salerno as rescues intensify on the Mediterranean Sea.

The bodies arrived Sunday on a Spanish naval ship carrying another 400 migrants rescued in the central Mediterranean.

United Nations High Commissioner for Refugees spokesman Marco Rotunno says the 26 dead were involved in a shipwreck two days ago off Libya. Details remained sketchy, but Italian media say others are believed to have perished and 60 people were rescued.

Humanitarian groups say some 2,500 migrants were picked up at sea in recent days, making it one of the most intense periods for rescues on the Mediterranean since Italy reached a deal with Libya to slow departures of smugglers' boats carrying migrants.