US State Department has confirmed that four US military personnel have been detained by the Libyan government.

“We can confirm that four US military personnel are currently being held in Libyan government custody,” said Jen Psaki, State Department spokesperson. “We are seeking to further ascertain the facts and ensure their release. We are in touch with Libyan officials on this issue.”

It is yet unknown why the American service members are being held, though it is believed that Libya’s Ministry of the Interior detained the four individuals, a senior US Defense Department official told CNN.