Thousands of United fans were evacuated from Old Trafford ahead of kickoff after a suspect package was found in the North-West quadrant of the stadium.
A code red security alert was announced over the public address system, with the Stretford End and Sir Alex Ferguson Stand evacuated first, although fans initially remained in the rest of the ground.
Greater Manchester Police have warned people to avoid the area around Old Trafford as they try to move around 75,000 to safety.
Police with sniffer dogs are inspecting the stadium for any sign of a suspect device.
MUFC (old Trafford) game has been abandoned, Fans are leaving the ground. Please avoid the area if possible.— GMP Traffic (@gmptraffic) May 15, 2016
United went into the game with hopes of overhauling rivals Manchester City for the final Champions League place, but potentially face a fixture headache as they prepare for next weekend's FA Cup final against Crystal Palace.