Police launched a manhunt in Sweden’s capital Friday for a suspect who rammed a truck into a department store in a likely act of terrorism — killing four people and injuring 15 others, officials said.

The vehicle plowed into a crowd on Stockholm’s busy Drottninggatan shopping district before barreling into the side of the Ahlens store, the country’s security agency said. Panicked pedestrians and shoppers were caught scrambling for safety.

During a news conference, police said they were seeking a man in a green jacket and hoodie with a mustache and beard.

Swedish National Police told NBC News that one person was arrested in connection with the rampage, but would not immediately say whether he was a suspect or the man they earlier described. Two others were brought in for questioning, but authorities say they are not suspects but may have information.