( CNN ) -- Texas authorities are investigating `` the safety of children '' at a ranch occupied by about 400 followers of polygamist sect leader Warren Jeffs , officials said Friday . An aerial view taken last year shows some living quarters at polygamist leader Warren Jeffs ' Texas ranch . Authorities have sealed off the 1,900-acre ranch near Eldorado and no one is allowed to enter or leave , officials with Child Protective Services and the Department of Public Safety said . The people living at the ranch are cooperating , authorities said . Escorted by police , social workers entered the compound in south central Texas at 8 p.m. Thursday after receiving `` a referral , '' said Child Protective Services spokeswoman Marleigh Meisner . Watch police seal off the compound » . Child Protective Services `` is conducting an investigation into safety issues of the children who live within the compound , '' she said . Meisner would not provide details about the referral but did say officials responded `` within days '' of receiving it . As of Friday morning , Meisner added , her agency had `` not determined that there is a safety issue with these children . '' Several law enforcement agencies are assisting with the investigation , said Tela Mange , of the Texas Department of Public Safety . `` The people at the ranch have been cooperative and they are providing the investigators with everyone they want to talk to , '' she said . Jeffs ' Fundamentalist Church of Jesus Christ of Latter Day Saints ( FLDS ) bought 1,900 acres near Eldorado four years ago and built the ranch , which they call the YFZ Ranch . It is now home to as many as 400 members who relocated from their Arizona and Utah compounds . Jeffs , the 52-year-old leader and `` prophet '' of the 10,000-member church , was convicted in Utah last year on two counts of being an accomplice to rape , charges related to a marriage he performed in 2001 . He still faces trial in Arizona on eight charges of sexual conduct with a minor , incest and conspiracy . State and local law enforcement agencies set up roadblocks around the ranch Thursday evening , preventing journalists from seeing what was happening on the property , according to Randy Mankin , editor of the Eldorado Success weekly newspaper . `` This came totally out of the blue , '' Mankin said . There were no indications of any violence around the ranch , he said . When CNN crews have visited the ranch , it was guarded by armed men equipped with night vision gear and other high-tech surveillance tools to prevent intruders . When CNN flew over the ranch in a small plane last year , the crew saw a massive temple , the three-story housing units where Jeffs ' chosen followers live , the water tower , the school and community center , the dairy and cheese factory and a massive concrete mill . The FLDS church openly practices polygamy in two towns straddling the Arizona-Utah state line -- Hildale , Utah , and Colorado City , Arizona. , but members living on their Texas ranch rarely venture into Eldorado , four miles to the south . Critics of the sect say it arranges marriages for girls as young as 13 , and that competition for brides may be reduced through exiling young men . If male followers are excommunicated , the critics claim , their wives and children can be reassigned to someone else . Jeffs is now being held in the Mohave County Jail in Kingman , Arizona , where he will be tried on charges of being an accomplice to incest and sex with minors . In November , Jeffs was sentenced to 10 years in jail after being convicted of two charges of accomplice to rape . E-mail to a friend .
NEW : State Child Protective Services agents interviewing children . NEW : No one allowed to enter or leave 1,900-acre Texas compound . Once home to hundreds of followers of polygamist leader Warren Jeffs . Jeffs in county jail awaiting trial ; sentenced to 10 years in prison last year .