Federal authorities are searching for four women from Afghanistan who left a program on democracy at the University of Virginia.
The U.S. State Department tells media outlets that two women went missing from the program on Wednesday and two left last weekend.
They were among more than 20 Afghan women, including teachers, judges and professors, who participated in the Global Perspectives on Democracy Program hosted by the university's Center for Politics. The three-week program ended Wednesday, when the remaining women returned to Afghanistan.
"At this point, there is not a lot of information," said Raphael Cook, a State Department spokeswoman.
Two of the women were identified as Zuhra Sadat and Hamida Sayedkhan, who were discovered missing on June 4. Identities for the other two have not been released.
A spokesman for the center said the women were not a threat to the community and that the main concern was for their safety.
"The Center for Politics was neither contracted nor expected to monitor participants' activities outside the educational programming," the center said in a statement.
The mystery behind the women's disappearance is unsettling to students on campus, but what they said they found more disturbing was that they weren't notified about it.
The university confirmed no safety alert was issued after the first two women left.
The State Department and Diplomatic Security are working to determine whether the women stayed behind by choice.
The disappearance comes nearly a year after three Iraqi students attending a similar exchange program at Virginia Commonwealth University went missing. University police investigated the disappearance in July and determined no foul play was involved.
The Associated Press contributed to this report.