Cambridge Police report a man was robbed of his bike around 3 a.m. outside 359 Green St. in Central Square.
Police say the man was approached by two men who grabbed his expensive yellow Cannondale bike.
When the victim resisted, one of the suspects displayed what was believed to be a black handgun. The suspects then took the bicycle, left Green Street and headed towards Franklin Street.
One suspect, who took out the gun, is described as White, in his 30s, 5'6" or 5'7" with dirty blond hair and wearing a gray hoodie, jeans and a bandana or gaiter-style face masks. The other suspect is described as Black, in his early to mid-30s, with a mustache and chin hair, thin and wearing a dark hoodie.
Police say they have stepped up patrols in the Central Square area.
Anyone with information can contact police at 617-349-3300, or visit the police Web site on how to submit an anonymous tip.