Authorities dismissed as untrue a rumor circulating Friday on social media that U.S. Immigration and Customs Enforcement agents were detaining undocumented immigrants at SEPTA's subway station at City Hall.

ICE officials said Friday night that the agency had not conducted any sort of operation at the station, which is a busy stop along the Broad Street Line.

SEPTA Transit Police Chief Thomas J. Nestel III said he was not aware of any enforcement actions there.

"There is a viral post circulating around Facebook that ICE is stopping people at City Hall station. Is this true?" a person asked Nestel on Twitter at 6:04 p.m.

"The Watch Commander tells me that there has been no unusual activity reported or seen at City Hall. This appears false," Nestel replied six minutes later.

ICE is not averse to letting the public know it is cracking down on undocumented immigrants.

The agency on Thursday announced to the media that it had arrested 186 "foreign nationals" in Pennsylvania, West Virginia and Delaware during a 10-day targeted enforcement operation.