MEXICO CITY: Parents of 43 Mexican students kidnapped and apparently massacred a year ago demanded a new probe into their fate on Thursday, accusing President Enrique Pena Nieto of ignoring their demands to solve a crime that has battered Mexico's image.

The families asked the government to launch a new internationally supervised investigation and to review Mexico's own investigators, after international experts cast doubt on Mexico's official account of the incident.

In a meeting with families on Thursday, Pena Nieto offered to set up a new unit in the attorney general's office to search for disappeared persons.

But he stopped short of authorizing a new international probe or promising to review former-Attorney General Jesus Murillo and other officials' involvement in the investigation for possible obstruction of justice, as the families had sought.

"I feel very hopeless because the government did not give us a response," said Cristina Bautista, mother of one of the disappeared students. "From the experts we have gotten a lot, from Pena Nieto, nothing," she said.

Pena Nieto came to power three years ago vowing to restore order in Mexico, where hundreds of thousands have died in violence linked to organized crime since 2007.

Restoring public trust in his government's ability to act against corruption and a perceived culture of impunity has become Pena Nieto's biggest challenge in the wake of the disappearances.

According to the Mexican government, the students were rounded up by corrupt cops who handed them over to a gang that burnt them in a nearby dump.

But in a report released earlier this month, international experts flagged deep flaws in the official investigation and rejected its central claim that the victims were incinerated in a garbage dump in Cocula, near Iguala.

On Thursday, Pena Nieto promised to follow recommendations from the international report and create a group of experts to analyze the Cocula dump, vowing to continue the investigation.

"We're on the same side. You and I are seeking the same thing: to know what happened to each and every one of your sons," Pena Nieto said, according to his spokesman who gave a press conference after the meeting.

But many doubt Mexico's ability to lead a fair investigation, after a government auditor last month exonerated Peña Nieto and his finance minister from any wrongdoing over purchases of homes from public contractors that aroused suspicions of conflict of interest.

Families, students and activists gathered in Mexico's historic central square waving signs with photos of the missing students and demanding that Pena Nieto stepped down. Some had vowed a 43-hour fast, but none appeared satisfied with the president's response.

"It was a requirement to go and see him," said Cesar Gonzalez, a father of one of the students. "Unfortunately... the government has never given us anything besides psychological blows."