Doctors in Ho Chi Minh City Thursday said that a pair of twin sisters aged two and a half years remain in critical condition after their mother fed them herbicide Sunday evening before drinking it herself.

To Khanh Duyen and To Khanh Ngan were brought to Children’s Hospital 2 that afternoon after four days at a hospital in their hometown in Phu Yen Province.

Their mother Nguyen Thi Thao, 21, allegedly added herbicide to their milk and consumed the poison herself Sunday evening following a family conflict.

Other members of the family found them and rushed them to hospital that night.

Thao recovered after doctors pumped her stomach.

The children remain in serious condition.