Two candidates declared themselves the winner of a tight governor's race on Sunday in volatile Chiapas state, the latest battleground between Mexico's conservative ruling party and the party of leftist presidential hopeful Andres Manuel Lopez Obrador.
Preliminary results showed only about 15,000 votes separating Juan Sabines, of the leftist Democratic Revolution Party, or PRD, and Jose Antonio Aguilar Bodegas, of the Institutional Revolutionary Party, or PRI. Fox's National Action Party also backed Aguilar in a last-minute alliance with the PRI.
With about 59 percent of the 4,761 polling places counted, Sabines was leading with 49.4 percent, or 340,244 votes, compared to Aguilar's 47.2 percent, or 325,086 votes.
As both candidates celebrated in the state capital of Tuxtla Gutierrez, the election threatened to escalate a nationwide political crisis in Mexico, where tensions still run high over last month's disputed presidential vote. Political protests have had the capital and the southern city of Oaxaca under siege for more than a month.
Lopez Obrador, who is spending nights in a protest tent in Mexico City's main plaza as he fights to overturn conservative rival Felipe Calderon's narrow advantage in an official tally, was keeping a close eye on developments in Chiapas.
His party ally Sabines, a 38-year-old lawyer and former Tuxtla Gutierrez mayor, said a PRD victory in Mexico's southernmost state would help stabilize the country.
Aguilar, a 56-year-old lawyer and former federal senator, has promised to govern for all and "leave behind the retaliation and persecutions" of the current PRD-backed administration in Chiapas.
In a surprise move two weeks ago, Fox's National Action Party, or PAN, withdrew its candidate and threw its support behind Aguilar. It was the first time the PAN has formed an alliance with the PRI since Fox ended the PRI's 71-year hold on the presidency in 2000.
Many fear a loss in Chiapas by the PRD, could spark confrontations in Mexico's poorest state, which is no stranger to bloody clashes. Zapatista rebels rose up briefly here in 1994, and there has been sporadic violence since then between radical members of the political parties, although recent years have been quiet.