The travel advisory, issued on January 31, came in conjunction with the DOS ordering the departure of family members of US government employees from Belarus.
The state department cited Russian military activity along the border with Ukraine and the unpredictability of the situation as their chief concerns.
The DOS order also cited the US government's already limited ability to provide US citizens emergency services due to the Belarusian government's limitations on US Embassy staffing, as the potential of an armed conflict intensifies those concerns.
In the DOS' country summary, they claim "Belarusian authorities have detained tens of thousands of individuals, including US citizens, for alleged affiliations with opposition parties and alleged participation in political demonstrations. US citizens in the vicinity of the demonstrations have been arrested."
Concerns over Covid were also mentioned. The Centers for Disease Control and Prevention have a Level Three travel health notice for Belarus, indicating a high level of Covid in the country.
Belarus and Ukraine share a 674-mile border. According to reports, Russian troops have been steadily entering the former country. Russian and Belarusian officials say the build-up is to complete joint military exercises focused on defense.
On January 27, the Belarusian Ministry of Defence said the Russian troops will leave once the two militaries' joint exercises have been completed. The second phase of their joint exercise is set to take place between February 10 and 20.
On January 23, the US DOS issued a similar order for family members of government employees at the US Embassy to Ukraine in Kiev.
The January 23 travel advisory for Ukraine also cited Russian military activities on the Ukrainian border as their primary concern.