The requirement is for buses that operate across different cities and provinces, the ministry said in a guidance sent to local authorities Friday in an effort to curb the ongoing Covid-19 surge.

Cargo trucks and those carrying production materials can operate as normal.

For passenger buses that operate within the scale of a city or province, the ministry said local authorities could make the call to suspend services or adjust the number of trips to avoid mass gatherings.

Starting April 27, Vietnam has suffered a fresh Covid-19 outbreak in different clusters across the country. Previously, the nation had gone over a month without community transmissions of the virus.

As of Friday morning, infections have spread in 15 localities - Hanoi, Da Nang, Ho Chi Minh City, Ha Nam, Vinh Phuc, Hung Yen, Quang Nam, Dong Nai, Hai Duong, Yen Bai, Thai Binh, Bac Ninh, Lang Son, Quang Ngai and Thanh Hoa, with 121 cases confirmed.

As guided by the ministry, operators of railway, aviation, and inland waterway transport services will adjust their transportation schedules according to the situation on the ground.

Vietnam Railways Corporation has canceled many trips within northern Vietnam since Thursday as under the impact of the new outbreak, the number of passengers booking tickets has dropped significantly.