The estranged wife of internationally known pianist Vadym Kholodenko has pleaded not guilty in Texas to charges that she killed the couple's young daughters.

Sofya Tsygankova entered her plea on Wednesday, one day after she was charged with capital murder in the deaths of 5-year-old Nika Kholodenko and 1-year-old Michela Kholodenko.

Police affidavits say the children were found dead on beds in their home.

The Ukranian-born Kholodenko, the 2013 winner of the prestigious Van Cliburn International Piano Competition, discovered his daughters' bodies last Thursday.

The affidavits say Tsygankova was found bloodied and with wounds to her wrist and chest.

At one point she asked investigators, "Did I do anything bad to my kids?"

Police say Tsygankova sought mental treatment the day before the girls were found dead.