WARSAW, Poland (AP) — A Polish champion swimmer has reportedly swum non-stop across the Baltic Sea from Poland to the Danish isle of Bornholm in what Polish authorities are calling a tremendous feat.

Marcin Przeworski, a helper to 26-year-old swimmer Sebastian Karas, said Karas started from Poland's port city of Kolobrzeg on Monday evening. He tells The Associated Press that after more than 28 hours in the water, Karas reached a Bornholm beach, having covered 100 kilometers (62 miles). He says Karas was in a wetsuit and getting warm blended food every 40 minutes.

The Bornholms Tidende newspaper says Karas did make it across the sea and arrived in Dueodde beach late Tuesday.

The head of Poland's Swimmers' Association, Pawel Slominski, called it a "great feat" by Karas.

Jan M. Olsen in Copenhagen contributed