The "marathon" surgery began at 9 a.m. this morning.
By 11 a.m., doctors had completed a kidney separation procedure, the Corpus Christi Caller Times reported.
The twins were then moved to separate rooms around 11:45. There, reconstructive surgery took place on each child, with the doctors closing incisions using medically-expanded skin.
Around 1:45 p.m., their mother Silvia Torres told kristv that things were progressing well, with the twins hardly losing any blood and already adapting physically to the separation.
"It's a miracle."
— Fox News (@FoxNews) April 12, 2016
"To my tiny little fighters, whatever happens you have been an example to us that we should never surrender and always keep fighting."
"God is awesome. He has done a lot, and I thank the doctors and nurses for doing a very good job on my baby girls. Feeling anxious to see them already."
— Monster Energy news (@Monstenews365) April 13, 2016
"We don't care if they are conjoined or not. That's something God sent us, and we are going to do our best for this."
"Ten months that we've been with them, we have seen them growing and we have done so much work and preparation so that we don't miss any detail."
"I think that with all of the precautions that we are taking, that we're giving these twins the maximum chance for a positive outcome."
University of Maryland Medical Center said that the occurrence of conjoined twins happens once every 200,000 births. About 70 percent of conjoined twins are female. The overall survival rate of conjoined twins is somewhere between 5 percent and 25 percent.
Prognosis for Ximena and Scarlett looks good. As of 9:38 p.m., both girls were sleeping and doing great.
[Image via Kirayonak Yuliya/Shutterstock]