Nov. 3 (UPI) -- Austrian authorities confirmed on Tuesday that four people have died and almost two dozen were injured in a terrorist attack in Vienna they say was "motivated by hate."
At least one shooter armed with an automatic rifle opened fire in multiple locations on Monday night, including the street near a synagogue, officials said.
One attacker was shot dead by police outside St. Rupert's church. He was carrying an explosive belt and a bag filled with ammunition, investigators say.
Police on Tuesday identified the dead gunman as a 20-year-old man with dual Austrian and North Macedonian citizenship who had a previous criminal conviction for "terrorist association."
IS has claimed responsibility for the attack in a statement calling the shooter a "soldier of the caliphate."
Authorities were searching for others who may have been involved in the shooting, and police said Tuesday in a statement that they have arrested 14 people and conducted searches of 18 residences during their ongoing investigation.
"It is still unclear whether a second gunman is at large, however, it is possible the gunman acted as a single perpetrator," police said.
Authorities have warned residents to stay indoors and students to stay home from school.
The attack occurred while crowds of people were gathered at Vienna bars and restaurants prior to a new COVID-19 lockdown that was set to begin at midnight.
The shooter, who was killed by police at the end of the attack, was an IS sympathizer, Austrian interior minister Karl Nehammer said. Police have searched his apartment and are looking for accomplices, he added.
"It was an attack motivated by hate -- hate for our core values, hate for our way of life, hate for our democracy in which all people are equal in rights and dignity," Austrian Chancellor Sebastian Kurz said.
"We will not be intimidated by the terrorists. It is a battle between civilization and barbarism, and we will fight this battle with all determination."
Nearly two dozen people were injured in the attack, several of whom are in a "life-threatening" condition.
An officer who was shot during the incident is in recovery, police said.
Britain said it has in response increased its terrorist threat level to "severe," the second-highest rank on its five-tier scale, meaning "an attack is highly likely."
Home Secretary Priti Patel said in a statement it was raised from "substantial" as a precautionary measure and not due to a specific threat.