The storm made landfall in the early hours of Wednesday with wind speeds reaching 117kph (72mph) in the province of Quang Nam, home to the historic city of Hoi An and resort of Danang, the weather agency told state media.
More than 100,000 households with 400,000 people have been evacuated as of Tuesday. About 11,000 foreign tourists and 7,000 domestic visitors are staying in the city.
The government also said local authorities had instructed nearly 58,000 boats with 300,000 laborers to move to safe shelters.
Around 300 houses in the coastal province of Quang Tri had their roofs blown off late Tuesday as the wind began picking up speed.
There were no immediate reports of casualties, but photographs posted on social media and on state media showed downed trees and mudslides blocking roads.
Noru killed at least 10 people in the neighbouring Philippines after it made landfall on Sunday night, flooding farmland and communities and damaging crops, mainly rice.
Vietnam is also vulnerable to destructive storms and flooding because of its long coastline. Natural disasters – predominantly floods and landslides triggered by storms – killed 139 people and injured 150 others in the country last year, official data showed.
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