Mrs. Arroyo has charged that the documents were part of an opposition plot to launch a coup against her. She survived an impeachment complaint last month when her allies in the House of Representatives dismissed charges that she cheated in last year’s presidential elections.
"We are concerned over the negative implications of this incident on Filipinos who are building a career not only in the United States but also in other countries," Press Secretary Ignacio Bunye said in a statement.
"This is an embarrassment for our people who deserve an apology from those who messed up the good name of our country," he added.
Bunye said bilateral ties with the US remained strong "despite the shameful act of this political cabal," but expressed concern that "self-serving politicians can ruin our diplomatic integrity by spying on our allies."
Intelligence analyst Leandro Aragoncillo, 46, who worked at the White House for almost three years before leaving to take a job with the Federal Bureau of Investigation (FBI), allegedly gave Filipino politicians documents stolen from US Vice President Dick Cheney’s office.
A naturalized US citizen, Aragoncillo was arrested in New Jersey last month along with a former Philippine police official, Michael Ray Aquino, and also accused of downloading more than 100 classified documents from FBI computers.
Several opposition politicians, including detained former President Joseph Estrada, have all acknowledged receiving information from Aquino. But they all denied that they received classified US data.
Aquino, a known protegé of opposition Sen. Panfilo Lacson, has been indicted on charges of conspiracy and acting as an unregistered foreign agent.
Outgoing US Chargé d’ Affaires Darryl Johnson said the incident was "unfortunate and a cause for concern" but emphasized that it was an internal issue that would not affect Washington’s ties with Manila.
Johnson assured the suspects would get a fair trial.
Bunye said the espionage case is an internal US affair and that the Philippine government is leaving "the matter of bringing the malefactors to justice" entirely up to US law enforcement authorities.
US officials earlier said that Washington’s ties with Manila would remain "very strong" despite the espionage case.
The Department of Justice has ordered the National Bureau of Investigation (NBI) to investigate Aragoncillo’s possible links with opposition leaders.
NBI chief Reynaldo Wycoco led an NBI delegation to Washington to coordinate efforts with their US counterpart and determine if Philippine law was violated and national security had been compromised.
He said the US government is "taking the espionage case seriously and determined to run after everyone involved" because it was the first such breach of White House security in history.
"One special focus of the probe will be the source of funding of the conspirators, and this aspect will investigate the suspicious accounts and businesses of the concerned personalities," Wycoco said.
NBI officials said the US investigation is "focusing on a specific group of persons who benefited from Aragoncillo’s stolen information." They did not give names.
Justice Secretary Raul Gonzalez had ordered the NBI to look into any links between Aragoncillo and the opposition, especially money transfers to the former US Marine.
The bureau is to "immediately start the investigation of the alleged espionage case involving Leandro Aragoncillo... in relation to the high-ranking Filipino officials who are recipients/beneficiaries or co-conspirators in obtaining confidential, classified and secret documents," his order said.
Gonzalez ordered the NBI to look into "the money trail coming from the Philippines to Mr. Aragoncillo and Aquino, which will eventually establish the conspiracy between the duo and the supposed ranking Filipino officials."
Mrs. Arroyo has branded the opposition "robbers" and "coup plotters," suggesting that they stole information from the United States to be used in their continuing efforts to unseat her.
Aside from Estrada, Senators Panfilo Lacson and Jinggoy Estrada, Senate Minority Leader Aquilino Pimentel and Parañaque Rep. Roilo Golez have admitted to receiving information from Aquino but denied it came from stolen US documents.
Lacson, a former chief of the Philippine National Police and a former commander of Aquino’s, said he did not know if the information he received came from Aragoncillo, adding that it did not look like confidential information.
Estrada, who admitted to communicating with Aragoncillo, said information passed along to him and other opposition figures amounted to little more than summaries of Philippine media reports compiled by the US Embassy and shouldn’t be considered espionage.
Some Arroyo allies in the House of Representatives, such as Surigao del Sur Rep. Prospero Pichay, suspect the information contained in the US documents were purposely exaggerated by the opposition to turn public opinion against Mrs. Arroyo.
"Local authorities should explore possible violations of Philippine law and they should take appropriate action, especially if there are national security issues involved," said Bacolod City Rep. Monico Puentevella.
"The plain and simple truth is that this seems to be an open and shut case of espionage where the principals broke laws in the United States and possibly in the Philippines," said Marcelino Libanan of Eastern Samar.
Cebu City Rep. Antonio Cuenco said the investigation should also include what information was passed on to the opposition. — Aurea Calica, AFP