Interior minister Wolfgang Schaeuble also renewed a heavily criticised call for a change in the constitution to enable the government to deploy troops to bolster security inside Germany if needed.

Asked how officials planned to prevent trouble from hooligans, Schaeuble told the Bild am Sonntag newspaper: "I can promise that we will do what is humanly possible, and work closely with the security authorities of all participating states."

There is no 100% guarantee. At this World Cup, we are dealing with a new dimension of challenge - we must not just protect stadiums and team bases, but also the so-called public viewing areas, he added, referring to big-screen public broadcasts of matches.

Schaeuble, a conservative who took office in November, said he was satisfied with the security concept drawn up by the previous centre-left government for the June 9-July 9 tournament.

Source: RTE