Two passengers killed early Sunday in the crash of a sport-utility vehicle in Montgomery County have been identified as an 18-year-old woman and a 20-year-old man. Three other people in the vehicle, all of whom were hurt, also are young adults, police said.

Less than three hours into the new year, a 2007 Chevrolet Trailblazer was traveling west in the 4400 block of Jones Bridge Road in Bethesda, approaching Lancaster Drive, when it struck a curb in the predawn darkness, crossed a sidewalk, hit a chain-link fence and slammed into a tree, according to a preliminary police investigation.

Police have not said whether the five occupants were wearing seat belts or whether speed or alcohol played a role in the crash.

The front-seat passenger, Nicholas S. Clayton, 20, and the passenger directly behind him, 18-year-old Kaitlin M. Gallagher, were killed, Montgomery police Capt. Paul Starks said Monday. He said police have not determined where the two lived.

The Trailblazer had temporary D.C. license tags, Starks said. He said the driver, Roderick E. Brice II, 22, of the 12900 block of Clarks Crossing Drive in Clarksburg was transported to the Maryland Shock Trauma Center in Baltimore in serious condition.

With Gallagher in the back seat were Conor J. Hayes, 18, of the 5800 block of Nicholson Lane in Rockville and Kevin S. Russel, 19, of the 4700 block of Willard Avenue in Chevy Chase, Starks said. He said the two were taken to Suburban Hospital with injuries that were not life-threatening.

The cause of the crash remains under investigation.