Oil prices rose on Monday after Iran-backed Houthis launched missile and drone strikes against Riyadh, Saudi Arabia, on Saturday. The attacks heightened Middle East tensions as the United States and Iran remained in a stalemate. Brent crude futures gained 81 cents, or 0.78%, to $104.68 a barrel by 2202 GMT, while U.S. West Texas Intermediate rose 76 cents, or 0.76%, to $101.06 a barrel.