Troop drawdowns in Africa and Latin America would go against vital U.S. national security interests, commanders said.
The potential for cuts comes just as U.S. Southern Command is seeing a worrisome increase in Chinese and Russian investment.
Erik Prince has been referred to the U.S. Treasury Department for possible sanctions violations tied to a trip to Venezuela.
Members of the 13th Marine Expeditionary Unit will spend October in the U.S. Southern Command area of operations.
Roughly 600 service members participated in the Air Force's New Horizons humanitarian outreach program.
Navy Adm. Craig Faller warned Monday against Venezuela's "formidable weapon system."
A plan by Ecuador to let the U.S. use a Galápagos island for aircraft on anti-drug trafficking flights is drawing criticism.
The Venezuelan opposition leader has instructed his political envoy in Washington to open relations with the U.S. military.
The Navy hospital ship Comfort will deploy next month to the Caribbean and Central and South America to provide assistance.
The Pentagon has been consulting with the White House on ways it can support U.S. diplomacy in Venezuela.