Military intelligence officials, who asked not to be named, said on Tuesday that there could be another possible coup attempt to overthrow Gloria Macapagal Arroyo as rumours swirled of continued unrest among Marines over the dismissal of their commander in connection with the plot.
On Monday night, the army moved 500 Special Forces soldiers to the main base in Manila to guard against what commanders said was the possibility of unauthorised troop movements.
Despite their comments, the officials dismissed as rumours mobile telephone text messages circulating widely in Manila which spoke of an attack at dawn on Wednesday on Arroyo's palace.
SMS messaging is particularly common in the Philippines, and military intelligence officials said last month that retired soldiers had tried to recruit military rebels by texting them.
The president's economic advisers, fearing damage to recent improvements in the government's finances, are keen for an early end to the state of emergency.
Protests against Arroyo have
become more commonplace
State prosecutors pressed on with a purge of alleged coup plotters, filing rebellion charges against a lawmaker and a soldier.
"As long as the situation which led to the proclamation (of emergency rule) remains, there will be fewer reasons to lift it," National police chief Arturo Lomibao said.
Arroyo imposed her order, granting broad powers of detention, after the discovery of what she said on Friday was a conspiracy by members of the opposition, communist groups and "military adventurists" to bring down her government.
There have been a dozen coup attempts in the Philippines in the last two decades.
But critics say Arroyo, who last year survived an attempt to impeach her over allegations of vote-rigging and graft, exaggerates threats in order to put off potential plotters and shore up public support.
A military document leaked on Tuesday showed that the alleged conspirators had planned a rolling campaign known as "Final Talk 2" that would have culminated on 31 March with 200,000 people marching to the Malacanang presidential palace.
Not so popular revolt
"Should the mobilisation fall short of the expectation, they would mobilise again ... on May 1, where they intend to target around 500,000 participants to encircle Malacanang," it said.
Critics say Arroyo exaggerates
threats to shore up public support
Lomibao said rebels had planned to take over the main police camp, seize Manila's airport and kidnap him and two other officials.
Financial markets have recovered and Manila's streets have been quiet since the drama of last Friday, the eve of the 20th anniversary of the fall of dictator Ferdinand Marcos in a "people power" rebellion.
Despite the apparent hopes of coup plotters to stir up huge protests, security analysts say Filipinos have little appetite for another revolt.
State prosecutors filed formal charges in court against Crispin Beltran, a member of the lower house of Congress, and Lawrence San Juan, an army lieutenant, The two are among 16 people identified as leaders of the plot against Arroyo.
Police have sought charges against 14 others, including five left-leaning politicians who are being held in the lower house.