Cedars-Sinai Medical Center said in a statement that Marina Kovalevsky, 49, and her daughter, Yana, 26, were continuing to receive treatment at the hospital for their sickness.
The statement said the women were expected to remain hospitalized over the weekend. They were earlier said to be in stable condition.
An attorney for the women, Frank Capwell, said the two believed their poisoning may have been accidental, and that they did not remember anything unusual that would lead them to believe they were intentionally targeted in Russia.
Russian and U.S. authorities say they are investigating how the women, who returned to Los Angeles this week, fell ill late last month during a visit to Moscow. It remains unclear how they may have come into contact with thallium.
(compiled from agency reports)