(Fernando Llano ~ Associated Press)
Capriles waved from a truck that rolled through the vast expanse of supporters. The crowd overflowed from Bolivar Avenue, the widest downtown thoroughfare, which according to some estimates has a capacity to hold about 260,000 people. The authorities didn't provide a crowd estimate.
"Bolivar Avenue is too small for us," Capriles shouted to the crowd.
While President Hugo Chavez led a rally in western Venezuela, authorities were investigating the killings of two men in a shooting that erupted during an opposition campaign caravan in western Barinas state Saturday.
Capriles condemned the killings in his speech.
"On Oct. 7 we're going to defeat violence in Venezuela," Capriles said. "Our country is tired of the violence, of the division, of the confrontation. ... The time of hatred is going to be buried in Venezuela."
Justice Minister Tareck El Aissami said in a message on Twitter that a suspect was arrested in the killings, but he didn't immediately identify him.
Opposition lawmaker Julio Cesar Reyes said Saturday that a group of Chavez's supporters blocked the caravan and people on both sides were arguing when a gunman appeared and started shooting.
Opposition officials said both men killed were participants in the motorcade of Capriles supporters.
Chavez rallied thousands of supporters during weekend street events in Guarenas, a town east of Caracas, and in western Zulia state.
"It's impossible for us to lose," Chavez said at Saturday's rally in Guarenas. The crowd chanted: "Ooh, ahh, Chavez won't go!"
People grabbed at red T-shirts that were thrown into the crowd. Some stood on rooftops cheering, and women screamed as Chavez passed.
Yusneidy Rondon, a 26-year-old student, shouted and danced in the street after getting close enough to hand Chavez a letter.
"Chavez forever. ... I love him!" gushed Rondon, who said that in her letter she had asked the president to provide her with a computer, just as she now enjoys free university tuition.
While Chavez touted his achievements during his speech, he also said "self-criticism" is important and acknowledged that problems including a housing shortage and sporadic blackouts remain.
"There are reasons for many people to be dissatisfied with this government that I lead," Chavez told the crowd. But, he added, "On Oct. 7, it isn't at stake whether the light went out or not ... whether they've given me a house or not."
"Those are very important problems and we're working to solve them," Chavez said. "My socialist government is going to continue solving our big problems."
The race is expected to be tight. A recent poll by the Venezuelan firm Consultores 21 put the two candidates roughly even, with 46.5 percent saying they would vote for Capriles and nearly 46 percent saying they would vote for Chavez. The poll had an error margin of 3 percentage points.
Another survey by Datanalisis this month showed Chavez with a 10-point lead over Capriles, while 11 percent of those interviewed didn't reveal a preference.
Addressing the crowd in Caracas, Capriles criticized Chavez for what he called a long list of unfulfilled promises, noting that years ago the president pledged to clean up the sewage-filled Guaire River in Caracas and it remains badly polluted.
"Where's the cleanup? Pure chatter," Capriles told the crowd.
The opposition leader criticized what he called gifts by Chavez's government to other countries, and rattled off a list including a donation to a Puerto Rican music group, a hospital in Uruguay and prefabricated homes in Guatemala.
Capriles' supporters converged on the demonstration by marching down several avenues, blowing horns and whistles. Some chanted: "We see it, we feel it, Capriles president!"
"I'm marching for my grandchildren, for my future," said Segunda Palacios, a retired teacher. "We don't want a tyrant anymore."
She said if Chavez wins re-election, "that would be catastrophic for the country."