Irene Esser is the girlfriend of President López Obrador's most influential son. She obtained a US visa thanks to Donald Trump's modelling agency and has maintained a "close friendship" with the president, sources say.
Incumbent president Juan Orlando Hernández was declared the winner by 1.5%, but analysts cite evidence of sophisticated computer fraud. Opposition candidate Salvador Nasralla has flown to Washington DC for meetings Monday with the OAS and US State Department.
The Trump administration on Friday put its weight behind President Juan Orlando Hernández saying it found the Nov 26 election result was legitimate, despite "irregularities." Observers from the OAS said the election lacked "integrity."