Federal agents apprehended eight men from Tajikistan— a Central Asian nation that borders Afghanistan — because they were concerned the men could have been plotting a possible terrorist attack on U.S. soil, multiple sources familiar with the investigation told CBS News.

The eight men residing in Los Angeles, New York, and Philadelphia were taken into custody earlier this month and charged with violating civil U.S. immigration law by Immigration and Customs Enforcement. They remain in ICE custody and face removal proceedings, according to two of the sources who spoke on the condition of anonymity because they were not authorized to speak publicly about the probe.

Multiple sources told CBS News there was no evidence to suggest that a specific targeted attack was planned, and U.S. officials said there was no imminent threat to the homeland.

The individuals — who sources said have ties to ISIS — crossed into the U.S. via the southwest border between 2023 and 2024 but at the time, immigration officials had no information connecting them to the terrorist group. The eight migrants were arrested by ICE when they entered the U.S. without proper documents and were subsequently released into the U.S. with notices to appear in immigration court, according to a senior official at the Department of Homeland Security.