An estimated 80,000 supporters of pro-government candidate Carlos Duque attended a final campaign rally for Sunday's presidential election, which critics say has already been rigged by followers of Gen. Manuel Antonio Noriega.

Thursday's rally for Duque was smaller and less enthusiastic than one held a day earlier for opposition candidate Guillermo Endara, who had a more than 2-to-1 lead in an independent opinion poll released this week."Your presence here proves that the story of fraud is over," Duque told the crowd of about 80,000, many of whom had been brought by bus from outlying provinces. "This is why we will win."

The rally culminated a bitter campaign that pitted Duque, a Noriega crony and candidate of the National Liberation Coalition, or COLINA, against Endara, representing the U.S.-backed Civil Democratic Opposition Alliance, a three-party coalition opposed to Noriega.

The alliance held one of the biggest opposition rallies ever Wednesday, drawing more than 100,000 flag-waving supporters who chanted: "Not one day more."

"As much as a race between Duque and Endara, this election will be a referendum on Noriega's rule," said a Latin American diplomat.

Opposition leaders and U.S. officials, including President Bush, have said Duque forces plan to stage massive fraud Sunday to keep Noriega in power as Panama's military chief and effective ruler.

Endara has promised to try to negotiate Noriega's departure from the Panamanian Defense Forces and to fire him if he refuses.

The elections also may deepen the 2-year-old confrontation between Noriega and the United States, which has tried since 1987 to remove him with a combination of economic sanctions, covert propaganda campaigns and support for anti-Noriega forces inside Panama.