Typhoon Kalmaegi made landfall in Vietnam on Thursday after killing at least 114 people and flooding entire towns in the Philippines.
More than 260,000 soldiers are on standby for rescue efforts as winds of up to 92 mph (149 km/h) hit the country's coastline, according to Vietnamese media and the government's online portal.
Six airports in the country have been forced to close, and hundreds of flights are expected to be affected, the government warned.
The country, which has already been battling record rains and floods, is now facing one of Asia's strongest typhoons this year.
The typhoon could generate waves of up to 8 meters (26 feet) on the South China Sea, according to Vietnam's weather bureau.
The country's environment ministry stated on Thursday that the storm is on land, in the provinces of Dak Lak and Gia Lai. Hundreds of localities in seven cities and provinces are at risk of flooding and landslides in the following hours.
Reports indicate damages including roofs torn off homes, shattered glass panels at hotels, and trees uprooted along city streets and rural roads. In Quy Non, trees have fallen on major roads, and windows in hotels have shattered.
Kalmaegi made landfall in Vietnam at 19:29 local time (12:29 GMT). A few minutes later, residents in Dak Lak province began calling for help as their homes flooded.
Vietnam's military has mobilized over 260,000 personnel and resources to aid storm relief efforts, and officials are actively evacuating coastal communities.
In the Philippines, where Kalmaegi caused significant devastation prior to reaching Vietnam, President Ferdinand Marcos Jr. declared a state of emergency due to mass casualties and major damage.
Local tourist destinations like Hue and Hoi An recently faced floods after riverbanks burst, prompting evacuations and raising concerns about additional impacts from Typhoon Kalmaegi.
