MEXICO CITY: Gang suspects have confessed to killing 43 missing Mexican students, burning their bodies for 14 hours and tossing their charcoal-like remains in a river, authorities said, in a case causing national revulsion.

Facing angry protests in the biggest crisis of his administration, President Enrique Pena Nieto vowed to hunt down all those responsible for the “horrible crime.” Authorities say the aspiring teachers vanished after gang-linked police attacked their buses in the southern city of Iguala on Sept. 26, allegedly under orders of the mayor and his wife in a night of terror that left six other people dead.

The police then delivered the 43 to members of the Guerreros Unidos drug gang who told investigators they took them in two trucks to a landfill and killed them.

If the confessions are proven true, the mass murder would rank among the worst massacres in a drug war that has killed more than 80,000 people and left 22,000 others missing since 2006.

The Iguala case has drawn international condemnation, highlighted Mexico’s struggle with corruption and undermined Pena Nieto’s assurances that national violence was down.

“To the parents of the missing young men and society as a whole, I assure you that we won’t stop until justice is served,” said Pena Nieto, who has shortened a trip to China and Australia starting Sunday due to the case. Attorney General Jesus Murillo Karam stopped short Friday of declaring the 43 dead and said an Austrian university would help identify the remains.

He said authorities will continue to consider the students as missing until DNA tests confirm the identities.

But the chief prosecutor added that there was “a lot of evidence... that could indicate it was them.”

Three Guerreros Unidos members confessed to killing the male students after police handed them over between Iguala and the neighboring town of Cocula, Murillo Karam said, showing videos of the taped confessions.