Former Polish prime minister Jaroslaw Kaczynski says migrants who have arrived recently in Europe are carrying diseases that could hurt the local populations.

The words sparked a sharp rebuke from a left-wing politician, Janusz Palikot, who slammed Mr Kaczynski's words as racist language that Adolf Hitler "would not be ashamed of".

Mr Kaczynski, whose opposition Law and Justice party is expected to win parliamentary elections on October 25, told voters in Makow Mazowiecki: "There are already signs of the emergence of very dangerous diseases which haven't been seen in Europe for a long time: cholera on Greek islands; dysentery in Vienna; various types of parasites, protozoa, which aren't dangerous in the organisms of these people, but which could be dangerous here."

Meanwhile, Croatia's conservative president says her country might need to build a fence on its border to stop the migrant influx just as neighbouring Hungary has done - comments that are drawing criticism.

President Kolinda Grabar Kitarovic said: "I think some kind of a fence or physical barrier will be needed in the future."

She added: "I would like to avoid that, but I don't see how else we can protect ourselves," particularly if neighbouring countries close their borders with Croatia.

Hungary has sealed its border with Serbia and threatened to do the same with Croatia because of the tens of thousands of migrants crossing through to go to Western Europe. Croatia's liberal government has ruled out building a fence.

More than 170,000 asylum-seekers have passed through Croatia since mid-September.