THE SIGHT of desperate folk treading hard roads is familiar in Macedonia and Serbia. In the Kosovo war of 1999, more than 250,000 ethnic Albanians entered Macedonia; Serbia had to absorb even more of its own kin, for longer, after the Serb cause was defeated in various conflicts. But a new tide of migrants from further afield is startling for both countries.

On a road near Presevo in southern Serbia, once used mainly by farmers, a couple of young women trudge onwards, chattering in Arabic, followed by a larger Middle Eastern group of 20 with children, then a cluster of Africans. Tomor Misini, an ethnic Albanian war veteran, leads a group of local volunteers who help the travellers.

Since early June the number of migrants using this route, having set out from places like Syria, Afghanistan or the Horn of Africa, has risen four or fivefold to about 1,000 a day. Their immediate goal is Hungary, a European Union member whose borders have hitherto been porous.

Several other things have changed very recently. First, Serbia and Macedonia have largely stopped stemming the flow; they just send people north, giving migrants a 72-hour pass to cross each of their territories. Secondly, Hungary started building a giant fence on July 13th, to Serbia’s dismay.

A detention centre in Macedonia, where hundreds were locked up, has been emptied. A migrant route from the Aegean to central Europe that was previously clandestine and controlled by traffickers is now, at least on this leg, more open.

Until recently, migrants crossing Macedonia were banned from public transport. Many walked along a railway track to Serbia, where 24 died this year. Now they register and get the train to Tabanovce, near Serbia’s border. Then they traverse woods and fields to Presevo, where a registration centre opened on July 8th.

They get a Serbian document which notionally affirms their intent to seek asylum within 72 hours. In fact, most will not. With their document they also get a leaflet with train times to help them get to Subotica on the Hungarian border. In the railway station similar instructions are pasted up in English and Arabic. Once in Subotica the migrants walk across another frontier.