Germany shut down two train stations in Munich about an hour before midnight on Thursday following a tip from the intelligence service of a friendly country that the Islamic State (IS) militant group was planning a suicide bomb attack.
The action by German authorities added to jitters in many capitals as Europe ushered in the New Year with heightened security after a year of militant attacks, the biggest of which killed 130 in Paris in November.
The stations - Munich's central station and Pasing station some 8 km (5 miles) away - reopened several hours later after the tip-off could not be substantiated.
Bavarian Interior Minister Joachim Herrmann told a news conference on Friday that Germany had received a tip from another country's intelligence service that IS planned to attack Munich. He did not name the country but German television said in an unsourced report that the tip-off came from France.
Five to seven suicide bombers were to take part in the attack, Munich police chief Hubertus Andrae said at the same conference.
"The Federal Criminal Police Office informed the Bavarian police on New Year’s Eve of the existence of a tip-off from a friendly intelligence agency that Islamic State plans a concrete attack, attacks tonight, at midnight at the Munich central station or/and Pasing (station),” Herrmann told reporters.
"I believe this decision was right because I think we cannot take unnecessary risks when we are dealing with such concrete threats, concrete locations, and a concrete time,” he said.
Security fears in Europe were heightened two days ago by Belgium’s decision to cancel New Year’s Eve celebrations in Brussels, citing a suspected plot to carry out an attack in the capital.
Belgian police said late on Thursday three people were being held for questioning as part of an investigation into the plot.
Security was also beefed up in Berlin, where one million people welcomed 2016 at the landmark Brandenburg Gate.
Shortly after the Paris attacks, German police cancelled a friendly soccer game between Germany and the Netherlands in Hanover because of fears of a planned bomb attack. No arrests were made and no explosives were found after the cancellation.
Last year was the deadliest year of militant attacks in Europe since 2004. Evidence that two of the Paris attackers had entered the continent under cover of a wave of Middle Eastern refugees heightened anxieties over the migration crisis.
Munich police tightened security across the southern state of Bavaria, which was the entry point from Austria for virtually all of the just over one million asylum seekers who arrived in Germany last year.
German Chancellor Angela Merkel has rebuffed pressure to clamp down on migrant arrivals along Bavaria’s border with Austria.
Opposition to her stance grew at home and abroad after two of the suicide bombers in the Paris attacks were found to have carried fake Syrian passports.
In an apparent effort to allay those concerns, Germany said on Thursday it would start holding personal hearings for asylum seekers from Syria as of Friday, reversing a policy of granting almost automatic refugee status for Syrians.