Sweden, Denmark tighten borders

Sweden on Monday imposed controls on travelers arriving from Denmark in a bid to curb an unprecedented influx of refugees, prompting knock-on measures from Denmark that triggered fresh concern for Europe's Schengen passport-free zone.

Hours after the Swedish controls on a major bridge-and-tunnel link with Denmark went into effect, the Danish government, which fears being saddled with large numbers of migrants, announced it would implement spot checks on its border with Germany.

Alarmed by the restrictions, which come as both Germany and Sweden grapple with record migrant numbers, Berlin warned Europe's Schengen zone was "in danger".