Marches are being held throughout Mexico to protest against a wave of killings, kidnappings and shootouts sweeping the nation.
The rallies are being held in each of Mexico's 32 states, with up to 500,000 people expected in the capital Mexico City alone, organisers say.
Many protesters say the government is unable to curb the violence.
Some 2,700 people have been killed in Mexico this year, most of them victims of drug-related attacks.
More people are now kidnapped in Mexico than in Colombia or Iraq, with more than 300 reported attacks so far during 2008.
Emergency plan
The protests are being organised by a number of anti-crime groups, who have urged demonstrators to march in silence with candles or lanterns.
In Mexico City, the main boulevard - Reformer - is gradually filling with demonstrators, the BBC's Duncan Kennedy says.
They are due to start marching to the capital's main plaza, Zocalo Square.
Many are carrying national flags - a sign that they want a unified country in the fight against crime, our correspondent says.
Some 4,000 police officers are being deployed in the capital to provide security during the march.
Many protesters blame the government for what they say is its inability to combat crime.
This is despite a series of tough measures unveiled in recent years by President Felipe Calderon, including the deployment of more than 25,000 police and troops around the country to wrest Mexico from drug cartels.
Last week the country's political and security leaders launched an emergency programme to try to combat the rising wave of violence.
Measures include sacking corrupt police officers, two new prisons for kidnappers and strategies to combat money-laundering and drug-trafficking.
http://news.bbc.co.uk/2/hi/americas/7590272.stm
