Guatemala President Jimmy Morales ordered the head of a United Nations anti-corruption commission be blocked from entering the Central American country just four days after shutting down the mission.
The UN's International Commission Against Impunity in Guatemala had been investigating corruption in the country but its mandate was ended by Morales on Friday.
The government said in a statement that it considers Colombian Ivan Velasquez "a person acting against order and public safety."
It said his actions were impacting on the "governability, institutionality, justice and peace in the country."
Velasquez is currently attending meetings in the United States, said Matias Ponce, CICIG spokesman.
Morales's move not to renew CICIG's mission came after it made a joint request with the state prosecutor's office to lift his presidential immunity as part of an investigation into campaign finances.
Both the Commission and prosecutors presented evidence that Morales' FCN-Nacion party failed to report nearly one million dollars in financing to electoral authorities during his successful 2015 presidential campaign.
Set up in 2006, the mission is an independent body with investigative and prosecutorial powers. Its success in tackling corruption has inspired calls for similar bodies to be set up in other Central American countries.