The senator was part of a U.S. delegation visiting the Colombian border city of Cucuta, where humanitarian aid is being stockpiled for planned delivery to Venezuela.
In a televised interview, Rubio declined to say explicitly if he would support U.S. military intervention against Venezuela.
The U.S. has continually tried to send humanitarian aid to Venezuela via its allies in the Caribbean and in Colombia, but is attempting to import the items without state approval under the guise of a philanthropic gesture. Last week, both the International Red Cross and the Red Crescent refused to participate in the operation which tries to circumvent Venezuelan leadership.
Venezuelan President Nicolas Maduro has repeatedly stated that Venezuela requires no aid from the United States. It has, however, received some aid from other allies to offset the economic blockade being applied by the United States.
The U.S. delegation included Carlos Trujillo, the U.S. ambassador to the Organization of American States, and Republican U.S. Representative Mario Diaz-Balart of Florida.
Rubio, a former presidential candidate, does not have the authority to call for specific actions but sits on the U.S. Senate’s Foreign Relations Subcommittee on Western Hemisphere, Transnational Crime, Civilian Security, Democracy, Human Rights and Global Women's Issues, which handles legislation related to Canada, Mexico and South and Central America.