The world's second-most powerful tropical cyclone of 2024, Yagi has already killed at least 16 people in the Philippines, having formed east of the archipelago earlier in the week.
The typhoon hit island districts of north Vietnam about 1300 local time (0600 GMT) on Saturday, generating winds of up to 160km/h near its centre after losing power from its peak of 234km/h in Hainan on Friday.
Super Typhoon Yagi has made landfall in northern Vietnam after tearing through southern China. (AP PHOTO)
Vietnam's coastal city of Haiphong, an industrial hub with a population of two million that hosts factories from foreign multinationals and local car maker VinFast, has been hard-hit by the winds.
Parts of the city experienced power outages on Saturday, authorities said.
The wind smashed buildings' glass windows and broke tree branches, according to a Reuters witness.
City streets were deserted as citizens heeded authorities' calls to stay indoors.
Earlier in Hainan, which has a population of more than 10 million, the storm knocked down trees, flooded roads and cut power to more than 800,000 homes.
Authorities in Vietnam evacuated almost 50,000 people ahead of Yagi's arrival. (AP PHOTO)
Vietnam evacuated almost 50,000 people from coastal towns and deployed 450,000 military personnel, the government said.
It also suspended operations for several hours at four airports on Saturday, including Hanoi's busy Noi Bai, cancelling more than 300 flights.
High schools were also closed in 12 northern provinces, including in the capital Hanoi.
Typhoons are becoming stronger, fuelled by warmer oceans, amid climate change, scientists say.
Typhoon Shanshan slammed into southwest Japan at the end of August, the strongest storm to hit the country in decades.
Yagi is named after the Japanese word for goat and the constellation of Capricornus.
