Mexico's president has left on a six-day trip to China and Australia amid angry protests over the suspected massacre of 43 college students by a gang allied with corrupt police.
Angry protesters tried to break into Mexico City's National Palace late Saturday, while others torched several trucks in the southern state of Guerrero, where the students vanished in September.
Thousands of people marched in the capital over a case that has repulsed the nation and triggered the biggest crisis of President Enrique Pena Nieto's administration.
The protests came a day after authorities said suspected Guerreros Unidos gang hitmen confessed to receiving the 43 students from local police, killing them, incinerating their bodies and dumping them in a river in Guerrero.
Authorities said they are still waiting for DNA results to confirm the identities of the remains.
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But the apparent mass murder has shattered Pena Nieto's attempts to move Mexico's narrative away from years of drug violence and toward the economic reforms that has earned him international praise.
Despite the unrest, Pena Nieto left for China to attend an Asia-Pacific Economic Cooperation (APEC) summit before a two-day state visit in the country. He will then travel to Brisbane for a G20 summit before returning on November 15.
Pena Nieto defended the trip, telling reporters it would be "irresponsible" for him to miss summits that are important for Mexico.
Amnesty International criticised his decision, saying it "shows the lack of interest in confronting the grave human rights situation in Mexico."
Gang-linked police shot at busloads of students in the Guerrero city of Iguala on September 26, in a night of violence that left six people dead.
The police then handed the 43 abducted students to the Guerreros Unidos.
Prosecutors say the city's mayor, worried the students would interrupt a speech by his wife, had ordered the police to confront them. They are among 74 people, including police and gangsters, detained in the investigation.
