Surgeons in northern California successfully separated 2-year-old identical twin girls conjoined at the chest and abdomen after a painstaking, daylong operation, doctors said on Tuesday.

Angelica and Angelina Sabuco, marked with different-colored ribbons to tell them apart, entered the operating room at about 6:30 a.m. local time under the care of a team of 15 to 20 doctors and other medical personnel at Stanford University's Lucile Packard Children's Hospital in Palo Alto.

The toddlers emerged some 10 hours later, at about 4:30 p.m., unconscious, under sedation and breathing on ventilators, Dr. Gary Hartman, the lead surgeon, told a news conference.

Thank God for everything, their tearful mother, Ginady Sabuco, said in a brief statement she read to reporters as she choked back sobs. This is a dream come true. Words cannot express how we feel.

Hartman, still dressed in his surgical gown, said the two girls were doing well in recovery after the operation and would remain hospitalized for about two weeks, including a week in intensive care. Once discharged, he said, they are expected to spend a few additional weeks recovering at home.

Once they're healed, one would really expect them to be able to lead healthy lives, he said.

The separation phase of the surgery ran until about noon, after which the sisters were moved into individual operating rooms for the reconstructive phase of the procedure, Hartman said.

The girls, classified by doctors as thoraco-omphalopagus twins, were born joined at the chest and abdomen with fused livers, diaphragms, breast bones and abdominal walls. They have separate hearts, brains, kidneys, stomachs and intestines.

Hartman said the liver and all other shared tissues were essentially divided equally between the two sisters.

Dr. H. Peter Lorenz, the chief plastic surgeon on the team, said each girl would bear a vertical scar running from the middle of the chest to the belly button.

Doctors said special plates were inserted into each twin's sternum to reinforce their breast bones, which Hartman said underwent aggressive remodeling.

The sisters, who were born in the Philippines and now live in San Jose, California, can count to 10 and love stories and music, according to the hospital.

Tuesday's operation marked the sixth set of conjoined twins that Hartman has separated during his career.

In the United States, about six such surgeries take place every year. But 75 percent of conjoined twins do not survive pregnancy, according to the hospital.

The hospital said the cost of the surgery was covered under the family's private insurance plan. The family had approached Hartman soon after the girls were born, and he had followed their progress since then.