Nguyen Nhu Thang and Nguyen Thi Tam, both 46, were buried under rocks, earth and concrete on the Yen Hoa Bridge in Tinh Gia District, Thanh Hoa Province in north central Vietnam.
They and three other people were crossing the bridge in the early morning, just after the storm made landfall in northern Vietnam at around 4:30 a.m.
The storm uprooted trees in the northern port city of Hai Phong and caused strong waves that broke the embankment along the city’s Do Son Beach.
It also caused downpours in the nearby Quang Ninh Province, home to the famous Ha Long Bay, but did not cause major impacts to daily activities. Fishing boats and cruise ships in the province have been called back to shore the previous day.
Heavy rains were brought to Nghe An Province, which borders Thanh Hoa, flooding paddy, vegetable and seafood farms.
Other places in the storm’s path have not reported much damage so far.
The second storm to hit Vietnam this year, Mun has weakened and is set to become a tropical depression. Storm Pabuk hit southern Vietnam in January and caused no casualties.
Weather forecasters said the north and north-central regions, including the capital Hanoi, should expect heavy rains and thunderstorms today.
Natural disasters, mostly floods, storms and landslides, killed 181 people last year and left 37 others missing and caused losses of around VND20 trillion ($858 million).