Danish police did not name the suspect, but said only that a "young man" had been arrested on Friday and suspected of "complicity in the perpetrator's actions."

He is expected to face a remand custody hearing on Saturday.

On February 14, 22-year-old Omar El-Hussein is alleged to have used an assault rifle to kill Danish filmmaker Finn Noergaard at a free speech event in the capital Copenhagen. Hours later, early on February 15, El-Hussein gunned down security guard Dan Uzan outside a synagogue before he himself was killed in a shootout with police.

Two alleged accomplices were arrested soon after the attacks and charged with aiding and abetting the perpetrator. They were remanded in custody for 10 days, and on Thursday a Copenhagen court extended their detention by four weeks.

The two have denied charges of being accessories to murder, attempted murder and violence.

nm/sms (AFP, AP, dpa)