Forensic experts have identified one of 43 missing Mexican students among charred remains found in a landfill, officials said, partly solving a case that has roiled the government for weeks.

"One of the pieces (of bones) belongs to one of the students," a federal official told the AFP news agency on Saturday on condition of anonymity.

Sources close to the families identified the victim as Alexander Mora.

Al Jazeera's Adam Raney, reporting from Mexico City, said a team of forensic specialists from Argentina who were chosen and trusted by the families of the missing students, confirmed that the remains identified were his.

Federal authorities had sent the badly burned remains to an Austrian medical university last month, on the recommendations of the Argentine forensic team, after finding them in a garbage dump and river in the southern state of Guerrero.

Authorities say the aspiring teachers vanished after gang-linked police attacked their buses in the city of Iguala on September 26, allegedly under orders from the mayor and his wife in a night of terror that left six other people dead.

The police then delivered the 43 young men to members of the Guerreros Unidos drug gang, who told investigators they took them in two trucks to a landfill, killed them, burned their bodies and dumped them in a river.

"The decision goes a long way in confirming the events the attorney general has been telling the country for the past few weeks," our correspondent said.

The case has ignited indignation across Mexico and abroad for the fact that the students disappeared at the hands of a corrupt local government and that federal authorities took 10 days to intervene.

Tens of thousands have taken to the streets, some calling for President Enrique Pena Nieto to resign.