Thousands of protesters caused commuter chaos by closing off Mexico City's business district to traffic on Monday (July 31), pressing the main leftist candidate's demand for a vote recount in a presidential election he says was stolen from him. Launching a campaign of civil disobedience that raises the stakes in Mexico's political crisis, Andres Manuel Lopez Obrador's supporters seized control of the capital's imposing Zocalo square on Sunday (July 30) night as well as a six-mile (10-km) stretch of the elegant Reforma boulevard. They set up tents and huge tarpaulin covers in the middle of the wide, tree-lined avenue, cutting off all commuter traffic on Monday morning. The avenue is home to Mexico's stock market, many luxury hotels, government offices, headquarters of major corporations and the U.S. embassy. The several thousand demonstrators did not close down buildings so workers were allowed into their offices, but the occupation caused long delays for many commuters. Some were furious. "What awaits us is a populist president calling people to the streets to hurt the rest of the population. We had transparent elections, supervised by them, and now he (Lopez Obrador) wants to be president no matter what," said Mexico City resident Eduardo Vallejo. The Mexican peso fell 0.52 percent to 10.9160 to the dollar on Monday morning as investors became nervous about the protests. Lopez Obrador apologized to those who do not back his cause but said his campaign to overturn the July 2 election that he narrowly lost to conservative ruling party candidate Felipe Calderon would save Mexico's young democracy. "The fight to stop democratic from sliding back is causing some difficulties for a group of citizens and for those difficulties we ask sincere forgiveness," said Lopez Obrador's campaign manager, Jesus Ortega. Local police could break up the protests but that is unlikely as the city and its police force are run by Lopez Obrador's Party of the Democratic Revolution. He was mayor until he stepped down last year to run for president. "We are offering that if there is a recount of all the votes we will stop calling for demonstrations. We will respect the results of the recount," Lopez Obrador told his supporters on Monday. Calderon's margin of victory was just 244,000 votes, or less than 0.6 percentage points, and Lopez Obrador says results from more than half of polling stations were tampered with. The election battle is now with Mexico's highest electoral court, and Lopez Obrador is trying to push it into ordering a full recount in the coming weeks, while Calderon insists there was no fraud. The leftist led a demonstration of several hundred thousand people on Sunday (July 30) and stayed in the Zocalo all night. The seven judges have to decide whether to reopen some or all of the ballot boxes by Aug. 31. That means Lopez Obrador's occupation of the capital could last for weeks. Polls show that while slightly more than half the country thinks Calderon won cleanly, more than a third believe there was fraud and about half want a recount.