The Greek government and the UN refugee agency have brought in extra staff and ships to deal with some 25,000 stranded migrants on the island of Lesbos, the BBC reports.

A processing centre has been also set up on an abandoned football ground to help the migrants to get to Athens.

A Greek minister said on Monday Lesbos was “on the verge of an explosion”.

Meanwhile, hundreds of migrants broke through police lines on Hungary’s border with Serbia and started walking towards the capital, Budapest.

The migrants faced down pepper spray used by police as they broke out of a holding centre in a cornfield and marched down a motorway towards Budapest. They later agreed to be taken by bus to another reception centre.