MEXICO CITY -- Mexican President Claudia Sheinbaum on Monday said she was lobbying hard to dissuade US legislators from approving a tax on remittances to Mexico.

Mexico's migrants in the United States, regardless of their immigration status, "keep the United States economy running" by paying taxes, Sheinbaum said at a press conference. "Only 20 percent of what they earn" goes towards remittances.

There is "an agreement signed in 1992 between the United States and Mexico stating that there should be no double taxation, which would be discriminatory," she said of a 1992 treaty on the avoidance of double taxation.

Mexican lawmakers and non-governmental organizations have been tirelessly campaigning to expose the flaws of the proposed tax and its potential negative impact on the US economy, she added.

Taxing remittances could encourage undocumented migrants to seek other informal means of sending money to Mexico, which would fuel the black market, according to financial experts.