A crack was discovered Saturday on the section of the highway that runs through the Mekong Delta province’s Binh My Commune, Chau Phu District, the Vietnam News Agency reported. The crack was 30 meters long and a centimeter wide, and there were signs it was expanding.

Initial investigations indicate that the crack was caused by a change in the flow of the nearby Hau River, which runs parallel to the route, coupled with a weak foundation in the earth, officials said.

Two houses and two stores in the area where the crack appeared have been evacuated by provincial authorities. Barriers and warning signs have been erected, and traffic has been re-routed to relieve pressure on the area where the crack has appeared.

Local authorities said they also plan to reinforce structures, find out which area is most vulnerable to collapse and keep track of the situation, among other actions.

National Highway 91 is a 142-kilometer-long road in the Mekong Delta, running from Can Tho City to a border gate with Cambodia in An Giang Province.

Land erosion has become a frequent occurrence in many coastal and riverine provinces in Vietnam, claiming hundreds of houses in the last decade.

It has become a particularly acute problem in the Mekong Delta, Vietnam's food basket that grows half of its rice and accounts for 90 percent of its rice exports.

The delta is losing 500 hectares of land to sea and river erosion every year, according to the Ministry of Agriculture and Rural Development.

It is estimated that by 2050 the lives of one million people will be directly affected by this.

The Ministry of Construction last year submitted a proposal to build concrete barriers to protect 44,800 families in the region.