Anger and frustration over the case of Mexico's 43 missing students erupted in violence Saturday as protesters set fire to vehicles outside the Guerrero statehouse, and demonstrators in Mexico City torched the main doorway of the National Palace on the Zócalo central square.

Parents and classmates of the 43 disappeared students from the Ayotzinapa Normal School in central Guerrero told VICE News that they rejected the statements made Friday by Mexican attorney general Jesus Murillo Karam, who said the young normalistas were almost surely killed and burned in a mass grave near the city of Iguala, Guerrero, where the initial police attacks took place September 26.

"I am keeping the faith that he is alive," said Ezequiel Mora, whose 19-year-old son Alexander vanished that night after he and others were detained by Iguala police.

Protesters at a government building in Chilpancingo, Guerrero. (Photo by Hans-Maximo Musielik)

On Saturday afternoon, Ayotzinapa students and supporters once again attacked the central state government building in Guerrero's capital, Chilpancingo, and set fire to several vehicles that were turned over and rammed into the fortified gateway of the government complex.

Ayotzinapa students promised that more "direct actions" will take place in the coming days until they receive precise evidence that their missing classmates are dead. In the meantime, they told VICE News that they believe the 43 students are still alive, and they blame what they called inadequate and shoddy investigative work on the part of federal officials for failing to find them.

Protesters rammed vehicles into the gateway of the Guerrero statehouse on Saturday. (Photo by Hans-Maximo Musielik)

Ernesto Guerrero Cano said in an interview Saturday at the Ayotzinapa campus that Murillo Karam's statements "were a lie." He said more protests and actions against the state are certain to take place until the missing students are found.

"Something good has to come out of all this," said Guerrero Cano, 23.

Late Saturday night, demonstrators cheered when an intense blaze erupted at the door of the National Palace, the symbolic seat of Mexico's government. The fire was quickly extinguished, but the torching of the palace door signals the most direct assault on a government building in Mexico by civilians in generations.

ARDEN LAS PUERTAS DE PALACIO NACIONAL ... Mucha gente se retira después de estos actos ... (Vía mi TL) — Risco (@jrisco)November 9, 2014

On Friday, Murillo Karam said the students were killed on the night of their kidnappings by Iguala municipal police officers working for a local drug cartel called the Guerreros Unidos. He said human remains found in a remote dump in the community of Cocula will likely never be fully identified due to how severely they were burned.

Near the end of his press conference, the nation's chief prosecutor attempted to ignore further questions by saying "Ya me cansé," or "Enough, I am fed up," before reporters. The statement quickly caught the attention of social media users, as Mexicans on Twitter and Facebook said they too felt a need to declare "#YaMeCansé," in reference to the violence, lawlessness, and impunity that reigns over much of the country after nearly eight years of the military-led and US-backed drug war in Mexico.

Photos by Hans-Maximo Musielik