Typhoon Kalmaegi, which killed at least 114 people in the Philippines, is barrelling towards central Vietnam with increasing windspeeds.
Thousands of people who live in coastal communities have been asked to evacuate ahead of its arrival, which is expected to bring waves of up to 8m (26 ft), according to Vietnam's weather bureau.
Kalmaegi, one of the strongest typhoons this year, is likely to cause further devastation in a country which has already been battling record rains and deadly floods over the past week.
More than 50 flights have been cancelled or rescheduled, while six airports in the region have suspended operations.
Vietnam's Deputy Prime Minister Tran Hong Ha called Kalmaegi a very abnormal storm and urged local officials to treat it with urgency.
Earlier on Thursday, Philippines President Ferdinand Marcos Jr declared a state of calamity after the typhoon left a trail of deaths and devastation in his country.
The storm has flooded entire towns on Cebu, the region's most populous island, where 71 deaths were reported. Another 127 are missing and 82 injured, according to officials.
Cebu provincial authorities reported a further 28 deaths that were not included in the tally released by the national civil defence office.
President Marcos Jr made his declaration due to the extensive damage caused by Typhoon Kalmaegi and in anticipation of another storm, Uwan, expected to hit the Philippines over the weekend.
Almost 10 regions, around 10 to 12 regions, will be affected. So if that many areas are involved, with that kind of scope, then it's a national calamity, he told local media.
A state of calamity allows for better access to emergency funds and expedited relief efforts for those affected.
Local officials described the havoc wrought by the storm as unprecedented. Residents returning to their destroyed homes are reeling from the deadly floods earlier this week.
Typhoon Kalmaegi, locally known as Tino, is the 20th tropical cyclone this year to hit the disaster-prone Philippines. Just a month earlier, back-to-back typhoons caused significant casualties and destruction.
The storm also threatens nearby Thailand, with local officials warning of potential flash floods, landslides, and river overflows.
