A day ahead of midterm elections in Mexico anti-Government protesters have violently clashed with police.
The government has moved some 40,000 members of security forces in to restive southern states in a bid to safeguard the vote.
In Oaxaca at least two officers were captured by protesters who want a boycott of the elections.
They are angry about the continued internal strife and gang violence that has claimed more than 100,000 lives in the last eight years.
Perhaps the most high profile case involves the disappearance, last September, of 43 student teachers in Guerrero state.
The demonstrators say they were almost certainly massacred by drug cartels in league with local police.
The lower house of Mexico’s Congress, nine state governorships and more than 1,000 posts in state legislatures and mayors’ offices are up for grabs in Sunday’s election.
Sunday’s vote is the first test for President Enrique Pena Nieto since he was elected in 2012 on a mandate to bring peace to Mexico and boost economic development.
The polls suggest the ruling Institutional Revolutionary Party (PRI) should retain a slim working majority in the lower house of Congress, partly as the main opposition parties are riven by division.