Mexico City: Thousands of Mexicans marched in Mexico City on Saturday to mark 12 years since the disappearance of 43 college students, a case that shocked the country and became a symbol of its human rights crisis.

The victims' families marched along Reforma Avenue demanding truth and justice, as the fate of the students from the Ayotzinapa Rural Teachers' College remains unknown. They disappeared on September 26, 2014, in the southern state of Guerrero.

Protesters included student teachers who travelled from different states across the country and were recognisable by their shaved heads, according to Mexican media.

The Interdisciplinary Group of Independent Experts, or GIEI, said in its initial reports that authorities allegedly colluded with police, members of the armed forces and organised crime groups.

But despite dozens of arrests, the identification of bone fragments belonging to three students and government promises, no one has ever been convicted in connection with the case.

In August, former Guerrero Governor Ángel Aguirre was arrested and later ordered to stand trial for alleged forced disappearance in connection with the case. Prosecutors accuse him of ordering the concealment and destruction of evidence that could have helped clarify the students' whereabouts.