Investigators in Kansas have issued an endangered persons advisory for a mother and her two young daughters who they believe were "coerced to travel to Mexico to a religious rehabilitation facility."

In a press release issued by the Kansas Bureau of Investigation (KBI), officials said the whereabouts of Martha Unger, 23, and her daughters, Madilynn Grace Unger, 2, and Haylie Faith Unger, 1, are unknown.

Unger and her daughters were reported missing from their rural home in Haskell County just before 7 p.m. on June 28, according to the KBI. 

Investigators believe they may have been coerced to travel to Mexico to a religious rehabilitation facility with Corney and Elizabeth Klaasen.

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Corney and Elizabeth Klaasen (L), Madilynn Grace Unger, 2, and Haylie Faith Unger, 1, (Center) and Martha Unger, 23 (R)

Authorities are searching for Kansas mother Martha Unger, right, and her two daughters, Madilynn Grace and Haylie Faith, who they believe were taken to a "religious rehabilitation facility" in Mexico by Corney and Elizabeth Klaasen. (Kansas Bureau of Investigation)

It is not known what type of facility they were being taken to or where it is located. 

Officials said the Klaasens are believed to be driving a white and black Chevy Blazer with a Mexico tag.

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23-year-old Martha Unger, 2-year-old Madilynn Grace Unger, and 1-year-old Haylie Faith

According to the KBI, the whereabouts of 23-year-old Martha Unger, 2-year-old Madilynn Grace Unger and 1-year-old Haylie Faith Unger are unknown. (Kansas Bureau of Investigation)

The Klaasens are in their 50s. Corney is a male, described as being approximately 6 feet 2 inches tall and weighing around 200 pounds. He is clean-shaven and last known to be wearing jeans and a button-up shirt.

Law enforcement also believes that Martha Unger drives a 2015 white Ford Explorer bearing Kansas tag 301RJY.

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Suspected vehicle involved in missing persons case

Officials with the Kansas Bureau of Investigation said this is the Chevy Blazer the suspects are believed to be driving in connection to a missing mother and her two young daughters. (The Kansas Bureau of Investigation)

Officials with KBI said investigators wish to check the welfare of Martha and her children.

Authorities are asking for the public’s assistance to help locate them or any information that could help find them by calling the Haskell County Sheriff’s Office at 620-675-2289.

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KBI officials are also urging anyone who sees the subjects or vehicle to call 911 immediately.

Fox News Digital reached out to the KBI and the Haskell County Sheriff's Office for comment.