Travel restrictions are in place for US government employees in a Mexican border city due to threat concerns. Officials have confirmed that restrictions have been implemented. The city affected by these restrictions is Nogales, Sonora.

Further details about the nature of the threats and the specific restrictions in place are available from the source. The restrictions apply to US government employees traveling to this area.

For more information, readers can refer to the original source, which provides additional context and details about the travel restrictions and the situation in Nogales, Sonora.