Only two of the sextuplets born to a Minnesota couple were still alive, and both remained in critical condition, hospital officials said.

The fourth sextuplet to die, Cadence Alana Morrison, died Saturday morning, officials at Children's Hospital in Minneapolis said Monday. Three of her brothers died within the first week of their June 10 birth.

Parents Ryan and Brianna Morrison of St. Louis Park released a statement through the hospital saying: "Though our difficult time continues, our faith remains strong. Our families, friends, and churches have provided us with great comfort, for which we are deeply grateful."

The couple also thanked hospital staff, and asked for continued prayers of supporters.

Sextuplets Lucia Rae and Sylas Christopher, remained in critical condition Monday in the hospital's neonatal intensive care unit.

The babies were born about 4 1/2 months early. The smallest of the six weighed only 11 ounces at birth, and the largest was a little over a pound.

Hospital officials said no further information would be released and the Morrisons were not talking with the media.

The Morrisons, both 24, spent more than a year trying to conceive before Brianna Morrison started taking fertility drugs, according to the couple's Web site.