Austria has re-imposed controls on its border with Hungary, with police checking vehicles at the main regular crossings and soldiers patrolling other stretches of the border.

Police say the controls that began Monday are meant to ensure that no one crosses illegally and to prevent the smuggling of migrants into Austria and other EU nations. They have reported more such smuggling attempts into Austria since countries along the Balkan migration route closed their borders to migrants earlier this year.

Before that, tens of thousands of migrants seeking better lives in prosperous EU countries came through Hungary and then through Austria until Hungary sealed its borders last September with razor-wire fences.

Austrian police did not say how long the new border controls would remain.