Riot police armed with machine guns patrol the street outside the Pasing railway station on Jan. 1, 2016, in Munich, Germany. According to Joachim Herrmann, Bavarian secretary of the interior, there was intelligence regarding a terror attack planned for New Year's Eve in at least two Munich railway stations. Johannes Simon/Getty Images

UPDATE: 10:50 p.m. EST – German police said they had reopened the Hauptbahnhof and Pasing train stations after several hours following warnings of an imminent suicide terror attack late Thursday. Authorities said the planned attacks were linked to the Islamic State group. Police said they would remain vigilant as an investigation continues.

UPDATE: 8:55 p.m. EST – German authorites said five to seven people were involved in a suicide terror plot in Munich tied to the Islamic State group. Munich police President Hubertus Andrae said no arrests have been made in connection to the plot, the Associated Press reported.

UPDATE: 8:45 p.m. EST ­­– A Bavarian minister said the planned terror attack in Munich was tied to the Islamic State group, also known as ISIS, German news outlet DPA reported. ISIS took responsibility for last month’s deadly terror attack in Paris. Joachim Herrmann, interior minister of Germany's Bavaria state, said a foreign security service had tipped off German authorities of a possible attack.

During a news conference early Friday morning local time, German police said more than 550 police officers are active in Munich after two train stations were shut down due to warnings of an imminent suicide attack, Deutsche Welle reported.

UPDATE, 7:45 p.m. EST: German police said the people who plotted a terror attack in Munich have an “Islamist background,” Agence France-Presse reported. Police in Munich evacuated two train stations after receiving information about an imminent threat late Thursday.

Police said they had “reliable information” that a group of attackers planned to act as New Year’s Eve celebrations were taking place. A police spokeswoman said it was possible the attackers had selected other targets besides the two train stations. It is unclear if police have made any arrests.

UPDATE, 5:50 p.m. EST: Munich police warned of a possible terror attack Thursday evening after receiving two “concrete tip-offs,” German newspaper Deutsche Welle reported.

Original story:

Police in Munich have warned of the possibility of a terror attack Thursday evening and asked people not to gather in large crowds. Two train stations were evacuated due to the threat, CNBC reported.

"Due to existing information which we take highly seriously, there is an attack planned tonight," police said, according to NBC News.

The Hauptbahnhof and Pasing train stations have been evacuated as police said they would continue to provide updates via social media. It was not clear who was responsible for the threats.

The threats followed Brussels cancellation of its annual New Year’s Eve celebrations as European cities remained on high alert after last month’s Paris terror attacks that left 130 people dead and hundreds injured.