"I am giving you up to 5 o'clock this afternoon to stand down," Mrs. Arroyo said. "Past this deadline, the chief of staff is authorized to use reasonable force to dislodge your group quickly and efficiently and arrest you," she added.

The approximately 50 soldiers — protesting alleged government corruption and low pay — rigged the building with explosives, one of their leaders told reporters earlier this morning. "These explosives are set to defend our position," said the leader of the mutineers, Navy Lt. Antonio Trillanes. "If they try to take us down, we will be forced to use it."

The Australian ambassador to the Philippines, Ruth Pearce, and at least two Americans, were inside the complex when the insurgents took it over, government officials said. But around mid-morning Ms. Pearce and several others emerged from the building, apparently unharmed. Ms. Pearce and the others boarded five buses waiting outside the complex. The buses then drove from the area. It was unclear whether the Americans were with the group. Officials at the United States Embassy could not be reached for comment this morning.

The complex is in the heart of Makati City, the country's financial district, and has been the scene of previous coup attempts. Dozens of marines loyal to the government encircled the area this morning. 

The government refused to call the incident a coup attempt. "It is a mutiny," said a military spokesman, Lt. Col. Daniel Lucero. In her speech later, however, Mrs. Arroyo described the mutiny as "already hovering on the fringes of outright terrorism." 

On Saturday night, the presidential palace in Manila was barricaded with armored vehicles and soldiers in full battle gear patrolled outside. Mrs. Arroyo then announced that a mutiny had indeed been plotted and ordered the arrest of 10 junior officers of the armed forces for allegedly abandoning their posts, taking with them their firearms.

In a statement released earlier today, the rebelling officers demanded that the Arroyo administration step down. "We demand the resignation of our leaders in the present regime," the statement said. 

Lieutenant Trillanes, the insurgent leader, went on national television late this morning and challenged the administration to address the renegades' complaints. He specifically reiterated the alleged practice in the military of selling firearms and ammunitions to Muslim rebels in the south. "This war has been going on for 35 years," he said. "Many Filipinos have died in this war. They were killed by bullets from the armed forces sold to the rebels."

He also accused the military of staging the bombings in Davao City in March and April that killed dozens of people, including an American missionary.
Lieutenant Trillanes claimed that the mutineers had 2,000 supporters within the armed forces, but denied that they wanted to take over the government.

"We are not attempting to grab power," he told reporters at the scene today. "We are just trying to express our grievances against this government and against the chain of command of the armed forces of the Philippines."

Dozens of Filipinos, supporters of the mutineers, marched in Makati City this morning, before Mrs. Arroyo's speech. They carried banners and streamers bearing the words "National Recovery Program," the same program the mutineers said they wanted implemented.

Ignacio Bunye, Mrs. Arroyo's spokesman, said in a news conference in Manila before the president's speech that the government "will find a way to resolve this peacefully. Our communication lines are open."

Defense Secretary Angelo Reyes said on national television before the speech that the administration was trying to communicate with the insurgent soldiers. This morning, he called a television station to ask for the cellphone number of Senator Gregorio Honasan, who is accused of supporting the rebels. "We are looking into the possibility of sending in an emissary," Mr. Reyes said.

In Washington, the Bush administration expressed support for Mrs. Arroyo. A State Department spokeswoman, Joanne Moore, said, "No one should be under any doubt that we fully support the legitimate civilian government" of Mrs. Arroyo. She said the administration saw no "real threat" to the Arroyo government, but added, "Let there be no mistake that a military coup would have immediate negative consequences, including consequences on the bilateral relationship."

Former President Corazon Aquino, whose administration faced several coup attempts, called on the public to support the administration during an appearance on national television this morning. "I hope and pray that these misguided elements will realize that true reforms cannot be realized through the use of force," she said.

The mutineers, who call themselves "Soldiers of the Nation," complained about what they called corruption in the military and the government, low pay, poor training and favoritism. They also accused the military of being behind the recent bombings in the southern Philippines and of selling arms and ammunition to Muslim rebels on the island of Mindanao. They claimed the military was covertly aiding its enemies to attract more financial and military assistance from the United States.

The former armed forces chief of staff, Dionisio Santiago, met with the mutineers before Mrs. Arroyo's speech. He told reporters there was no way the Arroyo administration would step down. "I told them to wait for the election," he said. "I also told them that a live hero is better than a dead hero."

This morning, former President Joseph Estrada, who was ousted in a military-backed uprising in 2001, was transferred from a government hospital, where he has been confined for months, to the main military camp in Manila. It was not immediately clear whether the transfer was related to the mutiny. National Security Adviser Roilo Golez said the transfer was "tactical." Mr. Estrada is on trial on charges of accepting bribes and illicit payoffs. He has been in government custody since his ouster, which put then-Vice President Arroyo into power.