Polls opened in Mexico on Sunday in an election that could provide a boost for the opposition party amid concerns over escalating violence.
Elections were underway in 15 states, where 12 new governors and dozens of mayors and local lawmakers will be elected.
Security remained a key issue around the country as drug cartel violence made its mark on the elections. Last week, unknown gunmen killed Rodolfo Torre Cantu, the gubernatorial candidate for the Institutional Revolutionary Party (PRI) in Tamaulipas state in an ambush that killed three others.
It was arguably the most high-profile killing of a candidate since the 1994 assassination of presidential candidate Luis Donaldo Colosio.