Mexico's AMLO refutes blame for chopper crash Mexican President Andres Manuel Lopez Obrador says "neofascists" and conservatives are blaming the government for a helicopter crash that killed two opposition politicians

MEXICO CITY -- Mexican President Andres Manuel Lopez Obrador says "neofascists" and conservatives are blaming the government for a helicopter crash that killed two opposition politicians.

Lopez Obrador refused to speculate on what caused the crash, but military experts said no explosive devices were found in the wreckage.

Mexico asked the U.S. National Transportation Safety Board for help with a probe, but the U.S. government shutdown has delayed the request.

Lopez Obrador said Wednesday that social media videos that suggest the helicopter was shot down were the work of "neofascist groups who are angry about our victory and are trying to slander us."

The Monday crash killed opposition Gov. Martha Erika Alonso of the central state of Puebla and her husband, ex-Gov. Rafael Moreno Valle. Two pilots and a third passenger also died.