Sison's lawyer, Michiel Pestman, said Friday he had argued unsuccessfully for Sison's immediate release. Sison denied the charges against him in a lengthy statement in court, the lawyer said.

Pestman said he had been instructed not to reveal details of the case.

The Public Prosecutor's Office said only that the examining magistrate ordered Sison held in pretrial custody for 14 days. The next hearing was set for Sept. 7.

"The judge thinks there is enough evidence to hold him," Pestman said. "I think that's ludicrous." Sison was being held in solitary confinement, Pestman added.

Sison, 68, was arrested Tuesday in the town of Utrecht, where he has lived for 20 years. Dutch police swept through the office of his National Democratic Front and through at least seven other apartments, seizing computer hard drives, discs, files and books and questioning his aides. No one else was arrested.

On Friday, as the closed hearing was under way, demonstrators demanded Sison's freedom.

He is suspected of ordering the killings of Romulo Kintanar in 2003 and Arturo Tabara in 2004. The Communist Party of the Philippines, which the European Union designated a terrorist group in 2002, claimed responsibility for both slayings.

Protesters wore white headbands bearing the slogan "Free Joma," using Sison's nickname. Bands blared as the demonstrators chanted anti-fascist, pro-socialist slogans. Dutch-based leftist groups waved banners of solidarity.

Grace Punongbayan, a member of Sison's Marxist umbrella group, said Dutch authorities had tried and failed to bring charges against Sison before. "Now here comes another attempt to persecute him politically," she said.

Sison's wife, Julie, said she feared for her husband's health in prison, and was concerned he could die in his cell. "I have not been allowed to contact him, and I do not trust the doctors in prison," she told The Associated Press.

She displayed bruises on her arm which she said she sustained when police raided her home and prevented her from calling a lawyer.

Sison's attorney said, however, that his client was seeing a doctor and medications should be available. "I don't think there's any reason to be concerned about his health," he said.

In 1992, Kintanar and Tabara broke away from the mainstream Communist Party due to differences over whether to pursue Maoist revolutionary strategy, upon which Sison founded the party in 1968 and its armed wing in 1969.

Authorities have declined to disclose the nature of the evidence against Sison, but said it originated in both the Netherlands and the Philippines.

In Manila, presidential spokesman Ignacio Bunye said Sison would be given normal protection by his government during the proceedings.

"As a Filipino, he will be entitled to the regular consular assistance, which would include visitations and seeing to it that he is provided the legal assistance he would need," Bunye said.

He is standing trial in the Netherlands, where the alleged crime was committed. "We will just let the Dutch judicial process proceed," Bunye said.

The Philippine government has long sought to bring Sison home to face charges stemming from his leadership of the communist rebel movement. But no extradition treaty exists between the Philippines and the Netherlands. Manila removed one obstacle toward such a treaty last year when it abolished capital punishment.

Sison describes himself as a political consultant for the National Democratic Front, which has been engaged in off-and-on peace talks with Manila to end the 39-year insurgency.