Furious protesters attempting to break into Mexico City's National Palace set fire to its doors during nationwide demonstrations over the apparent massacre of 43 students who were allegedly kidnapped by local police and handed over to a gang.

Protesters on Saturday night slammed metal barricades against the palace doors and briefly set them on fire but were unable to get into the building, which is mostly used by President Enrique Pena Nieto for ceremonies and special occasions.

Hundreds of demonstrators burned several vehicles and threw firebombs at the government headquarters in Guerrero, the southern Mexican state where charred remains believed to be the missing students were found last week. More than 300 young people, many wearing masks, descended on the headquarters and burned around 10 vehicles, including trucks.

Mexico was confronted with one of the grisliest massacres in years of drug violence after gang suspects confessed to slaughtering the missing students and dumping their bodies either in a river or landfill.

The unrest is the steepest challenge yet to face Pena Nieto, who took office two years ago vowing to restore order in Mexico, where about 80,000 people have died in violence linked to organized crime since 2006.

The latest round of protests were set off after Mexico's Attorney General, Jesus Murillo, said Friday that three detained Guerrerros Unidos gang members told investigators they set fire to members of the group in a rubbish dump near the southwestern city of Iguala. The students had gone missing in Iguala on Sept. 26 after clashing with police on their way to a rally to protest proposed government educational reforms.

In taped confessions, the suspects said local police handed them the students between Iguala and the nearby town of Cocula. They then bundled the 43 in the back of two trucks, took them to a nearby landfill, killed them and used fuel, wood, tires and plastic to burn their bodies for 14 hours.

The confessions may have brought a tragic end to the mystery, but parents of the victims refuse to accept they are dead until DNA tests confirm their identities, saying the government has repeatedly told them lies. The students' apparent remains have been sent to Austria for independent forensic examination, as per their families' request.

"It appears that the federal government, with great irresponsibility, is interested in closing this matter because it's all based in testimony. There is nothing definitive," Meliton Ortega, uncle of a missing student, told AFP news agency on Saturday.

Authorities have so far arrested 74 people, including the ousted mayor of Iguala, Jose Luis Abarca, his wife Maria de los Angeles Pineda, 36 police officers and several gang members of Guerreros Unidos.

Al Jazeera and wire services