In the weeks before U.S. President Donald Trump's declaration this month that he would forge ahead with designating Mexican drug cartels as foreign terrorist organizations, Cabinet members and top aides from across the government recommended against it, five people knowledgeable about the matter told Reuters.

The recommendations, which some of the sources described as unanimous, have not been reported previously. They were driven in part by concerns that such designations could harm U.S.-Mexico ties, potentially jeopardizing Mexico's cooperation with Trump's efforts to halt illegal immigration and drug trafficking across the border, said two sources, including a senior administration official.

Another key concern was that the designations could make it easier for migrants to win asylum in the United States by claiming they were fleeing terrorism, the senior administration official and two other sources said.