Germany reintroduced temporary controls on its western and northern borders on Monday as part of efforts to combat irregular migration and cross-border crime, the interior ministry said.

Germany, the European Union's largest and most powerful nation, has brought police back to its border crossings in a bid to curb migration and stop Islamic terrorists. But many worry the era of a border-free Europe is coming to an end.

Germany has announced plans to tighten control at all of its land borders as part of a crackdown on migration, placing restrictions on a wide area of free movement known as the Schengen Zone.