ALONG THE SERBIA-HUNGARY BORDER (AP) — Exhausted, hungry and cold, they have been walking for miles. What little they have is carried in plastic bags. They camp in abandoned homes, followed by stray dogs hoping to snag a morsel.

Tens of thousands of migrants from the Middle East, Africa and Kosovo have been flooding in a torrent this year to Serbia's border with Hungary, hoping to cross illegally into the European Union nation and flee west to a better life. Many have been on the road for months.

The 180-kilometer-long (111-mile-long) border between Serbia and Hungary is flat farmland. Sometimes the migrants camp in the border area for days, hiding amid the crops, playing hide and seek with border patrols. Graffiti in Arabic, torn transit papers, ragged shirts and garbage litter the fields.

Serbian and Hungarian border teams carry night-vision equipment as they patrol the border night and day. The situation has become so bad so quickly that German police have recently come to help. Hungary is part of the European Union's Schengen passport-free travel zone but many migrants are seeking to reach Germany and wealthier EU nations.

Groups of five or six migrants, all in hoods, walk slowly along the highway or the rail tracks in Serbia, patiently waiting for the best time to try to cross.

If they are caught, they are either sent back to Macedonia or they seek asylum in Serbia, which buys them more time. Others make it across only to run into Hungarian authorities — some 25,000 migrants have been detained in Hungary so far this year alone, compared to nearly 45,000 last year.

This week, a van packed with more than 40 migrants swerved off the road in southern Serbia, injuring half of them, some seriously. The driver ran away.