I'm open to any fully funded position to students currently studying outside the U.S and are non U.S citizens. I'm not really country selective. Thank you.
For this type of internships, all I could find were these:
Ecole Polytechnique Federale de Lausanne (Switzerland): open to any undergrad around the world
https://sv.epfl.ch/summer-research
KU Leuven (Belgium): open to all undergrad and master’s students around the world
https://wet.kuleuven.be/english/internships
University of Zurich (Switzerland): open to all international students
http://www.biologie.uzh.ch/de/Studium/UndergraduateSummerSchool.html
If you want to do a research internship in the United States, this is also possible, even though they are usually not through formal programs like the ones listed above. Vanderbilt University used to have a program like these for international students, (the Vanderbilt International Scholar Program, or VISP), but it was discontinued after 2016.
The most feasible way to participate in a research internship in the U.S. as an international scholar would be to search for someone in your current undergraduate institution who may have connections with faculty in U.S. universities (colleagues, research collaborators, friends, acquaintances etc.), so that a faculty member who runs a lab in a U.S. university may recruit you as a visiting researcher/scholar for some time (e.g. x number of months). In these cases, it may be necessary that your home institution sponsors you and pays for your expenses while you are in the U.S. You would most likely need a J-1 (exchange/visitor) visa to travel to the U.S. for this purpose, but you will obviously have to get the internship first so that the U.S. institution can give you some of the required immigration documentation to apply for the visa. The advantage of this path is that you are not restricted just to the summer; your designated time for research can be set for any part of the year (this will depend on the academic calendar of your institution, your potential U.S. mentor's calendar, etc.).