The International Rescue Committee's chief says events on the Serbia-Hungarian border where police tear-gassed crowds of migrants including women and children reveal "a dark side of the European character."

David Miliband told The Associated Press in an interview Wednesday that "anyone with an ounce of morality feels appalled by what's happening in parts of Europe."

While lauding German leadership in tackling Europe's migrant crisis, the former British foreign secretary said that Hungary's decision to erect a razor-wire fence to stop the influx of migrants was "misguided and short-sighted, and when it's combined with bullyboy tactics it's obviously appalling."

Serbian doctors say two people were seriously injured and up to 300 have sought medical help after Hungarian police used tear gas and water cannons to stop migrants from entering Hungary.