ATHENS, Greece — Gangs of youths smashed their way through central Athens and Thessaloniki, torching stores and buildings after the fatal police shooting of a teenager in the worst rioting Greece has seen in decades.

Rioters torched the capital's massive Christmas tree in central Syntagma Square. Some protesters posed for photos in front of the blaze. Others sang the Greek version of "Oh Christmas Tree."

The windows of one of Athens' luxury hotels, the Athens Plaza on Syntagma Square, have been smashed. The lobby filled with tear gas or smoke. A hotel guard said guests were evacuated. A small fire is burning in the lobby of the Foreign Ministry opposite Parliament.

In Thessaloniki, dozens of buildings are being smashed and rioters are throwing Molotov cocktails.