At least one person was killed and 15 others wounded in Austria’s capital Monday evening in a suspected terrorist attack by multiple gunmen.

Interior Minister Karl Nehammer told ORF television that one of the gunmen was shot and killed by the police and a major anti-terror operation was continuing to arrest the others. 

“I would like to call on all our citizens to stay inside, stay at their premises and keep away from public places. An operation against suspected terrorists is still ongoing,” he said.

Several gunmen armed with rifles targeted people in six locations in Vienna’s city center around 8 p.m. local time (1900 GMT), according to the police.

One passerby was shot dead and 15 people were wounded, according to Vienna Mayor Michael Ludwig.

Seven of the wounded are in critical condition, including a police officer.

Austrian Chancellor Sebastian Kurz announced on Twitter that military units were being deployed in Vienna to support police anti-terror operations.