A senior envoy mediating talks to resolve Venezuela's political standoff said today that President Hugo Chavez's refusal to recognize the gravity of a 10-day-old national strike against his government is impeding a settlement and raising the potential for violence.

Cesar Gaviria, secretary general of the Organization of American States and a former president of Colombia, said the Chavez government and the growing opposition movement have begun to focus on how to hold early presidential elections, aiming for the first three months of next year. But Gaviria suggested that unless an agreement is reached within a week, Venezuela risks a repeat of the political violence that shook the country in April, when Chavez was briefly removed in a military-led coup d'etat.

Gaviria called on both sides to move quickly toward early elections. But he appeared to place much of the onus for doing so on Chavez, who has called the strike a media-created fiction to destabilize his four-year-old government.

"They [the government] say there is no strike," Gaviria told foreign reporters. "They say everyone is working. That what we have is sabotage in the oil industry, and because of such different views of reality, it is very difficult to have an agreement.

"I think both sides have to negotiate soon, in the next few days, or we will find increasing demands by the opposition, and that may take Venezuela to a confrontation with a high risk of violence."

As trash piled up on Caracas streets and gasoline supplies dwindled, strike organizers decided to extend the work stoppage for at least another day. Their most effective tactic so far has been paralysis of the oil industry, a vital part of the national economy and the main source of government revenue.

Gaviria's pointed remarks appeared designed to generate a sense of urgency around the negotiations, which began early last month but have not produced results. The secretary general has taken up semi-permanent residence here in hopes of negotiating a lasting settlement to a political crisis that has gripped this country of 23 million people for much of the past year.

Chavez, elected twice on a promise to help Venezuela's impoverished majority, has stirred up class resentment with his fiery rhetoric, domestic agenda and a foreign policy that has appeared to favor Iraq, Libya and Cuba over the United States. His support has dwindled to the mid-30 percent range, according to public opinion surveys, but some of his followers have vowed to defend his "social revolution" with violence if necessary.

A diverse opposition movement has demanded that Chavez resign or move up presidential elections scheduled for 2006. He has responded that changing the electoral timetable is not allowed by the constitution. Nevertheless, talks are moving toward doing so.

Rafael Alfonzo, an opposition negotiator, said his side is calling for a two-part referendum on Feb. 2. The first question would ask voters to amend the constitution, allowing for early general elections, and the second would set a date for the balloting. But Alfonzo said the opposition is also demanding Chavez's immediate resignation, although he would be allowed to run in the elections.

"We're not close," Alfonzo said. "The water is only to his mouth. We think by Saturday, it will be up to his nose."

The strike is the most enduring challenge Chavez has faced since April, when another national strike prompted street violence and the coup. The United States then pledged to work with an interim government put into place by the leaders of the coup. But this time, the Bush administration has backed Gaviria as he has sought to balance the interests of an economically powerful opposition movement and Chavez's ardent, mostly poor supporters.

"If the people of President Chavez think they lost power in an illegitimate way and they were not taken into consideration, that would be very risky," Gaviria said.

In recent days, the deteriorating economic and social conditions have complicated the talks. The killing Friday evening of three anti-government demonstrators, allegedly by a 37-year-old drifter, and recent pro-Chavez demonstrations at opposition-controlled broadcasting stations have angered opposition leaders and their followers, making it unlikely that the strike will be lifted without significant concessions from the president.

But the shutdown of the $40-billion-a-year national oil company, Petroleos de Venezuela, poses the most pressing problem for the government. Chavez ordered soldiers to board a second striking tanker today. But most of the company's private fleet remained at anchor in protest, and dissident oil company executives said the industry was producing less than a third of its usual 3 million-barrels a day.

The company provides the government with $9 billion a year. It accounts for15 percent of U.S. oil imports -- about 1.5 million barrels a day, more than half Venezuela's exports. But Gaviria warned today that the most immediate threat is the dwindling gasoline supply within Venezuela.

"What I'm really fearful of is that with the problem of transportation, we may not have enough food and we will have a food shortage, which may lead us to looting and riots," Gaviria said.

Opponents of President Hugo Chavez march in Caracas, where trash is piling up as fuel supplies dwindle. The opposition has become a diverse movement.A Venezuelan soldier directs residents in Caracas waiting to buy food during the 10th day of a national strike aimed at ousting President Hugo Chavez. Talks are focused on early elections.