Villagers are seen stranded on rooftops of houses after an under-construction dam collapsed in Attapeu, Laos, on July 24, 2018. (Xinhua/Vilaphon Phommasane)

UNITED NATIONS, July 24 (Xinhua) -- UN Secretary-General Antonio Guterres was saddened by the loss of life and significant damage caused by a break in a hydropower dam under construction in the Asian country of Laos, said his spokesman on Tuesday.

Guterres extended his condolences to the families of the victims and to the government and people of Laos, and expressed the willingness of the United Nations to provide support to the national rescue and relief efforts if required, said Stephane Dujarric, the spokesman, in a statement.

Several people were feared dead and hundreds of others remained missing after the dam collapse in the southern Laotian province of Attapeu on Monday evening.