Authorities cordoned off parts of Cua Bac, Pho Duc Chinh, Pham Hong Thai, and Nguyen Truong To streets in Truc Bach Ward, Ba Dinh District to remove the bomb discovered the previous day.
They banned the use of mobile phones and walkie-talkies in the vicinity.
Construction workers on Cua Bac found the bomb six meters below the surface while digging on Saturday night. The incident was reported to authorities, all activities were halted at the site and the workers were evacuated.
Combat engineers from the Hanoi High Command found the bomb had two intact fuses and said it posed a huge threat.
At 10 p.m. on Sunday people living within a 200 m radius from the bomb site were requested to move out for around two hours for the bomb to be removed. Soldiers and vehicles were dispatched to the site.
A woman carries a child away during the evacuation. The temperature was around 15 degrees Celsius at the time.
A person living on Cua Bac said: "While authorities said the bomb would be removed in around an hour, I thought it could take longer. The weather was also cold, and so I decided to take my family to a relative's house for the night. We will return tomorrow to be safe."
While the bomb was being removed, outsiders were requested not to enter the cordoned off area. Police officers searched the place thoroughly to ensure no one was still in the area.
At around 11:40 p.m. the bomb was removed from the site, loaded on to a vehicle and taken to another location to be defused.
As of Monday morning, the bomb has been safely detonated in northern Bac Giang Province, around 60 km away, said Ta Nam Chien, chairman of the Ba Dinh District People's Committee.
A girl cheers as hundreds of people return home after being told to keep away for an hour.
In June Hanoi authorities had found a 1.6-m bomb under the Long Bien Bridge over the Red River. The bomb was removed four days after it was found.
Hanoi was heavily bombed between 1965 and 1972 by the U.S. Air Force during the Vietnam War. In one fortnight (December 18-30) in 1972 alone, 36,000 tons of bombs were dropped on the city.
