Smoke rises from a burned-out sports department store in Athens on Sunday as officials survey the damage from a night of rioting. (Thanassis Stavrakis/Associated Press)Hundreds of youths, angry after police shot and killed a teenager in Athens, destroyed several stores and vehicles in the Greek capital, before the violence spread to the northern city of Thessaloniki on Sunday.

Protesters threw Molotov cocktails at riot police firing tear gas after an officer killed a 15-year-old boy Saturday night in Exarchia, a downtown Athens district of bars, music clubs and restaurants. The shooting occurred around 9 p.m. local time when a group of youths attacked a police patrol car, according to witnesses.

The violence was the most severe since rioting in 1999 during a visit to Greece of then U.S. president Bill Clinton. A teenager killed in a police shooting during a demonstration in 1985 sparked weeks of frequent rioting.

Witness accounts varied widely over what exactly happened Saturday, but police said two officers involved claimed they were attacked by a group of youths, and that they responded with three gunshots and a stun grenade.

A blurry video shot by a bystander from a nearby balcony that purportedly shows the shooting was aired by local television stations and posted on the internet. Two sounds that could be gunshots can be heard, but the image is too blurry and distant to show the sequence of events clearly.

Officers suspended, arrested

The two officers have been suspended, arrested and charged — one with premeditated manslaughter and the illegal use of a weapon, and the other as an accomplice. They are to appear before a court Wednesday. The Exarchia precinct police chief has been suspended.

Youths later smashed store windows and set cars on fire with gasoline bombs in central Athens. At least 24 officers were hurt by flying objects, officials said.

Six people were arrested, five of them for theft from damaged stores and one for carrying a weapon, police said in a statement.

On Sunday, the violence spread to the country's second-largest city, Thessaloniki. Protesters there attacked city hall, two police precincts, several shops, vehicles and a bank, witnesses said.

Interior Minister Prokopis Pavlopoulos promised a thorough investigation into the teenager's death and pledged "exemplary punishment" for anyone found responsible.

Both Pavlopoulos and Deputy Interior Minister Panagiotis Chinofotis submitted their resignations in the early hours of Sunday, but they were not accepted by the prime minister.

With files from the Associated Press