Supporters of opposition presidential candidate Corazon Aquino paralyzed central Manila this afternoon and evening with the largest rally of her campaign as the country prepared for voting on Friday.

Crowd estimates ranged from hundreds of thousands to 1.5 million in the downtown Luneta Park. Many observers agreed that it was the largest crowd since Pope John Paul II's visit to the same park in 1981, when perhaps 2 million gathered.

The 1983 funeral of Aquino's slain husband, Benigno, held elsewhere in Manila, drew the most recent comparable crowd.

President Ferdinand Marcos, campaigning for reelection, is to hold his final rally Wednesday night, also in Luneta Park.

Election law specifies that campaigning must halt one full day before the election.

Marcos generally has drawn smaller and less enthusiastic crowds than Aquino -- or than he did in past campaigns of his 20 years in the presidency.

Nevertheless his party organization is considered much stronger.

Aquino, 53, a latecomer to politics, has relied principally on the party organization of her running mate, Salvador Laurel, but also on business leaders who have responded to her denunciations of "crony capitalism" under Marcos Story, Page A15 .

Early Wednesday, soldiers attacked Aquino's motorcade north of Manila, smashed car windows, fired one shot and threatened the occupants of one car with death, United Press International reported. Aquino was not involved in the incident that occurred after her car had passed. No injuries were reported.

A military spokesman said the soldiers attacked a car carrying Lupita Kashiwahara, Aquino's sister-in-law and media coordinator, because they were taking unauthorized pictures and were taunting the soldiers.

Today's rally began as cars, buses and motorcycles bearing partisans of Aquino -- many dressed in their campaign's yellow color -- converged and brought traffic to a halt.

Yellow confetti rained down from high-rise buildings, horns honked and firecrackers exploded. Many people brought their children, giving the atmosphere of a school fair.

Tonight, Aquino's motorcade arrived to cheers. She finally took the microphone about eight hours after the rally began, setting off a din of chanting by tiring supporters and a fireworks display.

Aquino led the group in singing "The Lord's Prayer. "I am sure we have won the election," she said. "Marcos will not be able to stop this . . . it's our chance to write history."

Marcos, meanwhile, apparently pulled out of a scheduled appearance with Aquino on ABC Television's "Nightline" program, which would have been the campaign's closest thing to a debate.

Aquino rejected a call from Marcos for a debate on local television. She said she would not get a fair shake on the air due to government control of the format and interviewers. Initial press reports that the two candidates would appear together live from Manila on the Wednesday night edition of "Nightline" raised eyebrows here because they had been unable to work out a formula for a debate on Philippines' television.

Aquino, charging that TV stations here have given Marcos' campaign far more air time than hers, had insisted on a place and format that by her reckoning would not be under Marcos' control. He said her demands were unreasonable.

Addressing members of the major chambers of commerce in a Manila hotel this afternoon, Marcos said that the government's Commission on Elections had determined that the "Nightline" appearance would violate election law, because it would occur after the official close of campaigning Wednesday night Manila time.

Today, Marcos challenged Aquino to appear with him on Wednesday on a government channel's talk show. But Aquino, in a statement, reiterated that "Nightline" was the proper venue and said ABC had agreed to move it up by 24 hours to avoid the timing conflict. She called for the program to be broadcast simultaneously in the Philippines. "It is a national disgrace that we have to rely on a foreign TV network to provide a neutral TV forum," Aquino's statement said. "That is the price of years of Marcos' censorship of the media."

In a statement of his own tonight, Marcos ruled out any appearance with Aquino on "Nightline." He said, "This is degrading to have Filipino presidential candidates debate before a foreign audience with a foreign moderator."