The US Army Reserve has asked subordinate commands to assess the availability of six types of units that could be needed in 90 to 120 days under US Southern Command, according to an internal message reviewed by CBS News. Responses were due by September 25.

The units include a medical brigade, a forward surgical detachment, a military police brigade, an engineer battalion, a combat sustainment support battalion and an expeditionary sustainment command. The message does not name Cuba, give troop numbers, or specify an operation.

Multiple US officials told CBS the request is part of continued military planning focused on Cuba. No deployment orders have been issued, and the Army Reserve did not respond to CBS before publication.

Cuban President Miguel Diaz-Canel has accused Washington of portraying Cuba as a threat and said Cuba would defend its sovereignty.

The request comes amid months of escalating pressure, including Trump’s failed-state label for Cuba at the UN last week and Havana’s accusation of planned aggression.