Typhoon Kalmaegi, which killed at least 114 people in the Philippines, is barrelling towards central Vietnam with increasing wind speeds.
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, and 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, 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 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 which were not included in the tally released by the national civil defence office.
President Marcos Jr made the decision to declare a state of calamity because of the damage already caused by Typhoon Kalmaegi, and in anticipation of another storm Uwan, expected to hit the country 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.
In the Philippines, a state of calamity is a condition involving mass casualty, major damage to property, and disruption to livelihoods and normal life for people in the affected areas.
Most of the deaths in the Philippines were due to drowning, with reports of torrents of muddy water flooding towns.
Damage to Cebu's residential areas was extensive, with many small buildings swept away and a thick carpet of mud left by the retreating floodwaters.
Local officials described the havoc wrought by the storm as unprecedented.
Residents returning to their destroyed homes recount the deadly floods. Jel-an Moira Servas, a business owner in Mandaue city, described how she found herself waist-deep in water within minutes of the flooding.
The national disaster agency said over 400,000 people have been displaced in Cebu alone. The official death toll includes six crew members of a military helicopter that crashed on Mindanao island while assisting in relief efforts.
Emergency responders report being caught off-guard by the extent of the flooding, leading to overwhelming demands for assistance.
Typhoon Kalmaegi is the 20th tropical cyclone of the year to hit the Philippines and follows a string of powerful storms that have recently impacted the country.
As Vietnam braces for Kalmaegi, local officials are also warning of potential flash floods and landslides.
