In another terrorist attack in Europe, gunmen opened fire in at least six locations in Vienna, Austria killing at least four people, two men and two women, and wounding 17 including one police officer. The police killed a gunman and are searching for at least one other.

The killed gunman was wearing a fake explosive belt when he was taken down. He was armed with an automatic rifle, a handgun, and a machete.

According to Austrian authorities, the deceased were “an elderly man, an elderly woman, a young male passerby, and a waitress.” Seven of the 17 wounded, remain in critical condition.

Austrian SWAT teams raided the home of the killed gunman using explosives to breach his apartment’s door. They arrested several other people at the apartment.

Austrian officials have termed the incident an “Islamist terrorist attack.” The authorities continue the investigation for additional suspects.

The killed gunman was described as a 20-year man of Northern Macedonian descent. He had been convicted last year for being a member of ISIS after being arrested on his way to Syria to join the terror organization. In December, the man, who also possessed an Austrian passport, was released early from a 22-month prison sentence.

“We experienced an attack last night by at least one Islamist terrorist,” Interior Minister Karl Nehammer said to the media.

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“This is a radicalized person who felt close to IS,” Nehammer added referring to the Islamic State terror organization.

“Yesterday’s attack was an attack on our values and a completely useless attempt to weaken our democratic society or to divide it,” Nehammer said. “We do not tolerate this in any way or from anyone.”

Austrian Chancellor Sebastian Kurz characterized the incident as a “repulsive terror attack.” He said that an anti-Semitic motive for the attack can’t be ruled out since the shooting began outside Vienna’s main synagogue, which was closed at the time.

“One of the perpetrators was neutralized, but several perpetrators appear to still be on the loose,” he added. “They seem to also, as far as we know, be very well equipped, with automatic weapons. So they were very well prepared.”

The shooting began just after 8:00 p.m. local time on a busy street that is a hub for shopping and dining in the city center right outside Vienna’s largest synagogue, Seitenstettengasse Temple. Security camera footage, later posted to social media, shows the gunmen walking through Vienna’s busy streets shooting victims at random at six different locations. One of the gunmen was captured on video shouting “Allahu Akbar.”

“They were shooting at least 100 rounds just outside our building,” Rabbi Schlomo Hofmeister, a witness, described. He watched the shooting unfold from his window above the synagogue, as the gunmen began shooting at people sitting outside in the street.

“All these bars have tables outside. This evening is the last evening before the lockdown,” he said. “As of midnight, all bars and restaurants will be closed in Austria for the next month, and a lot of people probably wanted to use that evening to be able to go out.”

Police haven’t released any information as to the attack’s motive. All Jewish synagogues and schools remain closed as a precaution. In the neighboring Czech Republic, police increased security at the border with Austria and at Jewish institutions in the country.

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“Police are carrying out random checks of vehicles and passengers on border crossings with Austria as a preventive measure in relation to the terror attack in Vienna,” Czech police posted on Twitter.

Authorities are already sifting through nearly 20,000 videos that were shot by witnesses and security cameras in the area.

Police have mobilized a 35-man investigation team and have already gone through almost 20 percent of the captured videos.