Florida Governor Ron DeSantis has said he would send troops to Mexico on "day one" of his administration.
The street value of the cocaine is estimated to be approximately $1.2 million.
A number of people were injured in the crash as well but there were no immediate further details.
Lopez Obrador, who took office in 2018, developed a friendly working relationship with then-counterpart Trump.
The four unidentified Americans were in a white minivan with North Carolina license plates when they entered Matamoros, Tamaulipas on Friday.
Last fall, during Sukkot, Uri L’Tzedek and Jewtina y Co. joined forces to host the very first Darchei Tzedek/Caminos a la Justicia Immigration Retreat.
The US Department of Homeland Security (DHS) said on Thursday of the 998 children still separated, 148 were in the process of reunification.
Under the US State Department program, groups of at least five people will be expected to raise a minimum of $2,275 per sponsored refugee.