MANILA — President Ferdinand E. Marcos threatened Wednesday to use his powers "to the limit" to halt unrest in the wake of his fraud-tainted reelection, but opposition presidential candidate Corazon Aquino pressed ahead with a campaign of protest and civil disobedience aimed at toppling his regime.
Marcos' warning, in a written statement issued from his Malacanang Palace, appeared aimed at blunting the still-uncertain momentum of Aquino's protest campaign.
Several opposition leaders charged that the Marcos' threat indicated he is considering a declaration of martial law, which he imposed from 1972 until 1981. During his election campaign, however, Marcos said he considers military rule unnecessary unless urban warfare breaks out.
May Widen Boycott
Aquino, appearing at a post-campaign rally in Angeles City, 50 miles north of Manila, told a cheering crowd of 15,000 that she intends to widen her boycott of pro-Marcos businesses and mount a series of other protests until the regime falls.
"These actions . . . are not just for today or for this week," she told the supporters who thronged into an open plaza under a blazing sun. "Let us not stop until we have brought Marcos down."
Aquino and her supporters maintain that she was the true winner of the Feb. 7 presidential election. Marcos, who won an official count riddled with missing ballots and mysterious vote surges, says he is the legal winner.
Marcos, apparently nettled by the threat of wide-scale civil disobedience, told a caucus of his ruling New Society Movement that the boycott could seriously damage the economy, officials said.
Will Prevent Turmoil
"I will exercise to the limit the provisions of the law and the constitution to prevent turmoil," he said in his written statement.
He noted that he has "certain powers to dismantle the machineries of civil disobedience," but did not specify what measures he was considering.
The current constitution, written under Marcos' direction, grants the president the right to order "preventive detention actions" under which any person can be arrested and held without bail.
It also allows the president to suspend habeas corpus , which provides for the prompt release of a person in custody, and declare martial law.
A Message for Marcos
In an apparent response to the warning, Aquino told the throng in Angeles City, a farm market community and longtime opposition stronghold: "This is the message I want to send to Marcos and his puppets: Do not threaten Cory Aquino. She is not alone."
In the first of a series of post-campaign speeches planned for four regions of the country, Aquino said she believes her call for a boycott of Marcos-connected businesses is working, and she promised to announce new targets of the protest soon.
She spoke to the throng from atop a flatbed truck after her running mate, former Sen. Salvador Laurel, introduced her as "the duly-elected president-elect of the Republic of the Philippines."
Aides said they were delighted by the size of the crowd and asserted that it showed that the mass movement behind Aquino's presidential campaign has not lost its momentum, even though almost two weeks have passed since the election.
Evidence of the boycott's effectiveness was still only fragmentary, however.
The next major test for the opposition protest movement will come next week, when Aquino has called a "Day of protest and prayer"--a virtual general strike--for Feb. 26, the day after Marcos' scheduled inauguration for a new six-year term.
To the delight of the crowd in Angeles City, she warned Marcos to "heed the fate of Duvalier"--a reference to Jean-Claude Duvalier, the Haitian dictator who fled to France after his regime collapsed on Feb. 7.
She also called on friendly countries to withdraw their recognition from Marcos' regime as a means of further weakening the president's position. West Germany and Spain have called their ambassadors home from Manila in a sign of displeasure over the election, and European diplomats said more countries may follow suit soon.
Foreign Ministry sources quoted by United Press International said Marcos has received no letters of congratulations from foreign governments, a standard diplomatic courtesy when a head of state wins an election. New Zealand Prime Minister David Lange said in a letter released by his embassy that he will not congratulate Marcos for his reelection. He cited "serious doubts about the credibility" of the voting.
But Soviet Ambassador Vadim Shabalin offered congratulations to Marcos, who responded by saying he favored expanded trade with the Soviet Union.
Filipino officials said that White House envoy Philip C. Habib met with more Marcos aides Thursday, including Defense Minister Juan Ponce Enrile, but there was no word as to the contents of their talks.
A spokesman for the U.S. Embassy, Allan Croghan, said it appears likely that Habib will return to Washington early next week to report to President Reagan on his findings.