President Donald Trump has ordered the federal government to account for all U.S. assistance to Mexico over the past five years, as part of his effort to shore up security along the U.S.-Mexico border.

Secretary of State Rex Tillerson and Homeland Security Secretary John Kelly were in Mexico on Thursday for meetings with top Mexican officials about immigration and other matters.

U.S. Secretary of State Rex Tillerson, center, smi U.S. Secretary of State Rex Tillerson, center, smiles as Mexico's Foreign Relations Secretary Luis Videgaray, right, shakes hands with U.S. Homeland Security Secretary John Kelly at the Foreign Affairs Ministry in Mexico City, Feb. 23, 2017. U.S. Secretary of State Rex Tillerson, center, smiles as Mexico's Foreign Relations Secretary Luis Videgaray, right, shakes hands with U.S. Homeland Security Secretary John Kelly at the Foreign Affairs Ministry in Mexico City, Feb. 23, 2017.

Among points of tension is the possibility of Trump’s administration using U.S. aid to Mexico as leverage for his demands that Mexico pay for a border wall and do more to stem illegal migration.

Trump’s January 25 executive order gives the heads of government agencies 60 days to “identify and quantify all sources of direct and indirect federal aid or assistance to the government of Mexico” since 2012. It does not indicate what will be done with the information.

While it is difficult to quantify the indirect support the U.S. provides to Mexico through multilateral institutions, direct aid is readily available online.

The main sources of the assistance are the State Department and the U.S. Agency for International Development, which jointly operate the website www.foreignassistance.gov.

Its figures state: