Part of the Upper Newtownards Road has been closed between the Knock traffic lights and Cabin Hill Park on Sunday afternoon.
A number of homes have been evacuated, with Stormont Presbyterian Church made available for those affected.
Police area the scene and diversions are in place.
Police are currently attending a security alert at Upper Newtownards Rd in East Belfast. Part of the road is closed, diversions are in place
More top news
Ministers are ready to reduce the waiting time for Universal Credit payments following an outcry from Tory MPs, it has been suggested.
Storm Brian will bring strong or very strong winds across southern and western parts of the UK
Spanish prime minister Mariano Rajoy said he wants permission to dissolve Catalonia's government and to call an early election.