Protesting students display their streamers and placards at Oblation statue of University of Philippines, as they call on President Arroyo to resign
Pressure continued to mount Monday for Philippine President Gloria Macapagal Arroyo to resign over allegations of vote-rigging in the 2004 elections. Former president Corazon Aquino again called for Mrs. Arroyo to step down, and the opposition is planning protests in the capital later this week.

Sunday's statement by influential Catholic bishops, who stopped short of calling for the president's resignation, may have given Mrs. Arroyo a reprieve. But it failed to convince her critics.

During a mass in Manila Monday in this largely Roman Catholic country, former president Corazon Aquino said Mrs. Arroyo's resignation was the best option.

"The second path is the long and inherently contentious process of a congressional impeachment that can only generate more divisions on society and cast more suspicions on the threatened institutions of our democracy," said Mrs. Aquino. "I ask the president to spare our country and herself from this second option and make the supreme sacrifice of resigning."

Presidential spokesman Rigoberto Tiglao repeated that Mrs. Arroyo will not resign.

"I really can't understand why a sitting president would be forced to resign on the basis on things [where there is] no evidence that are legal for putting down a president," he said.

Opposition leaders are planning a peaceful protest on Wednesday to demand Mrs. Arroyo resign.

Previous mass protests ended in the ouster of two previous presidents, Ferdinand Marcos in 1986 and Joseph Estrada in 2001.

But so far, opposition calls for demonstrations against President Arroyo have largely gone unheeded.

Hotel manager Ed Samson says the country needs a new political system, not a new leader.

"I think the system has to be replaced. You don't need to replace the president, another president will come in, the same problem will come up and they'll want to kick him out. I think it's the system that is rotten," said Mr. Samson.

The political crisis has prompted two international ratings agencies, Standard and Poor's and Fitch Ratings to lower their outlook for the Philippines from stable to negative.

James McCormack, a senior director of Fitch Ratings, says the downgrade is due to the uncertainty.

"When we look at the politics in the short-term we really don't see any immediate solutions to the issue," he said.

Congress is due to debate an impeachment motion when it reconvenes on July 25.

Mrs. Arroyo admits talking to an election official during the 2004 presidential vote, but denies any wrongdoing, calling the phone call a "lapse in judgment."