An Austrian laboratory will analyze more human remains that could belong to some of the 43 Mexican students whose disappearance nine years ago triggered international condemnation, the government said Wednesday.
The announcement came a day after relatives of the missing joined thousands of protesters in Mexico City demanding justice on the anniversary of one of the country's worst human rights atrocities.
So far, the remains of only three of the victims have been identified by experts at the University of Innsbruck.
"We have other remains pending identification," Alejandro Encinas, a deputy minister responsible for human rights, said at a news conference.
Two sets of remains, out of more than 120 discovered, were waiting to undergo genetic analysis at the Innsbruck laboratory, said Encinas, who heads a government-appointed truth commission.
Experts from the Mexican attorney general's office would also carry out their own analysis of additional remains, he said.
According to Encinas, 132 suspects have been detained in connection with the case.
They include 41 members of Guerreros Unidos drug cartel, 71 police officers, a former attorney general, 14 members of the army and five other officials.
The students from a teacher training college had commandeered buses in the southern state of Guerrero to travel to a demonstration in Mexico City before they went missing.
Investigators believe that they were kidnapped by a drug cartel in collusion with corrupt police.
Interceptions of cartel communications by the US Drug Enforcement Administration indicate the students were mistaken for members of a rival cartel and that the buses they took contained drugs, weapons or money, Encinas said.
Last year, the commission branded the atrocity a "state crime" and said that the military shared responsibility, either directly or through negligence.
Independent experts and relatives have accused the government of President Andres Manuel Lopez Obrador, known by his initials AMLO, of withholding vital information.
"We regret that AMLO's response is to stand with (the army) and not with truth and justice," one of the parents, Emiliano Navarrete, said at Tuesday's protest.