By Tim Gaynor

PHOENIX (Reuters) - Tucson police on Monday released recordings of 911 calls reporting the disappearance of Arizona 6-year-old Isabel Celis, who authorities said may have been snatched from her bed last month.

The high-profile search for hazel-eyed Isabel, who was reported missing on April 21 from the home she shared with her older brothers and both parents, drew national media attention as volunteers and police combed streets and washes in her middle class Tucson neighborhood looking for her.

In the audio recording, Isabel's father, Sergio Celis, calmly tells the operator he wants to "to report a missing person. My little girl who's 6-years-old. I believe she was abducted from our house."

The operator asks Celis why he thinks she was abducted, to which he replies: "I have no idea. We woke up this morning and went to go get her up for her baseball game, and she's gone," he said, in the recordings posted on the ABC news website.

"I woke up my sons ... we looked everywhere in the house, and my oldest son noticed that her window was wide open and the screen was laying in the backyard. We've looked all around the house," he adds.

The operator asks him if the girl's mother is with him. He replies, "I just called her and told her to get her ass back here," and then breaks off into chuckle.

A subsequent call was placed by Isabel's 14 year-old brother, Sergio, who then gives the telephone to his mother Rebecca, who is agitated and becomes barely coherent.

"I went to work at seven this morning ... and she is five, six, could you please hurry and get someone over here," she says, breaking off apparently in tears. The operator later tells the mother that she needs her to "calm down."

Earlier on Monday, police said Isabel's two elder brothers had been placed in the sole care of their mother over concerns for their welfare.

Tucson Police Chief Roberto Villasenor said the girl's father, Sergio Celis, had agreed not to have any contact with his sons, who are now in the care of their mother, Rebecca Celis.

Villasenor told reporters at a news conference that Sergio Celis had entered a voluntary agreement with Child Protective Services to stay away from the children, but declined to elaborate.

"Child Protective Services said that this would be the best scenario at this point," he said. The police chief did not give the boys' ages or names.

The girl's parents have told police Isabel was last seen when she was put to bed on the night of April 20. The family awoke the next morning to find her bed empty. Authorities said a window to the girl's ground-floor room was open, and a screen was missing.

Police have said they are treating the girl's disappearance as a "possible abduction," but have yet to rule anyone out as a suspect.

In a news release on Friday, Tucson police said they had been in contact with Child Protective Services after becoming aware of "information regarding the welfare of the older Celis children," but did not elaborate.

Several days after Isabel vanished, Sergio and Rebecca Celis made a tearful public appeal for her safe return, pleading with their daughter's presumed abductors to "tell us what you want."

After making their brief, anguished appeal, they hugged volunteers who helped in a search for their missing daughter, then walked away without fielding questions from the media.

During the search in recent weeks, Villasenor said police have received more than 1,000 tips from the public. Police have also canvassed homes in a 3-mile (5-km) radius of the girl's home and searched the Celis house using sniffer dogs.

(Editing by Cynthia Johnston, Mohammad Zargham and Lisa Shumaker)