BERLIN (Reuters) - German Interior Minister Thomas de Maiziere said on Saturday closer cooperation with foreign security services was needed after a New Year's Eve security alert in Munich highlighted fears about an attack on German soil.
Shortly before midnight on Dec. 31, police cleared two stations in the Bavarian capital after a tipoff that militants from Iraq and Syria were planning attacks.
Police re-opened the stations a few hours later and have said they do not know if the suspects even exist.
De Maiziere said the threat of an attack had not diminished.
"In the new year the situation will remain very serious," de Maiziere told daily newspaper Bild.
"In future, we will depend more intensively than before on close cooperation with security services from other countries and the exchange of information."
German media have reported that authorities received the tipoff from a friendly intelligence service, possibly France.
Much of Europe has been on high alert since Islamist militants killed 130 people in Paris on Nov. 13. Several cities, including Brussels, Paris and Moscow, scaled back their New Year celebrations.
Some politicians have criticized German Chancellor Angela Merkel's open-door refugee policy, saying it makes it easier for Islamist militants to enter Europe undetected.
Germany last year registered just over 1 million migrants, many from Syria and other conflict zones in the Middle East and Africa, according to a media report, putting a strain on local services.
Merkel's conservative allies in Bavaria, the Christian Social Union (CSU), which has long wanted to put a cap on refugee numbers, is calling for tougher security measures.
It will next week propose making individuals convicted of being a threat to public safety wear an electronic tag, the Rheinische Post newspaper reported.
It also wants people with dual nationality who have fought for a militia abroad to have their German passport revoked.
The CSU resolutions do not bind Merkel's government in Berlin but they do raise the pressure on her over national security.
CSU boss Horst Seehofer told Bild am Sonntag the attack threat issue should be kept separate from Germany's refugee policy, though "it is true that the opaque nature of the refugee influx is being exploited for criminal ends."
(Reporting by Madeline Chambers; editing by John Stonestreet)