Updated

Hundreds of activists demanded Thursday that Philippine President Benigno Aquino III prosecute all officials, including some of his own allies, who allegedly stole from state funds intended to help the poor.

Carrying kerosene torches, the protesters marched to the presidential palace but were stopped by riot police who barricaded the road.

Three senators and several associates have been charged with plunder for allegedly receiving hundreds of millions of pesos (millions of dollars) in kickbacks from a businesswoman who skimmed the money from government allocations for the poor.

The protesters say all three senators belong to the opposition, and that any Aquino allies linked to the scam should also be charged.

Former Senate President Juan Ponce Enrile, Sen. Jinggoy Estrada and Sen. Ramon Revilla Jr. have denied any role in the scam. Plunder carries a maximum sentence of life imprisonment and is non-bailable. The anti-graft court hasn't issued arrest warrants.

"It is not enough for them to charge the three because they are all opponents of the president, they belong to the opposition," said former left-wing Congressman Teddy Casino. "What we want is to hold everyone involved accountable."

Renato Reyes, secretary general of the left-wing New Patriotic Alliance, accused Aquino of protecting allies linked to the scam.

"We are here to express our outrage over the current system, over the way government is being run, over the lack of political will in prosecuting the many plunderers who have emptied government coffers, who have stolen from the people," he said.

Among those linked to the scam by businesswoman Janet Napoles were Budget Secretary Florencio Abad and Agriculture Secretary Proceso Alcala. Both have denied any dealings with Napoles. Aquino has defended the two officials, saying those linking them to the scam were just "trying to muddle the issue."

Supporters of Abad say he is one of the president's closest allies and the strongest supporter of his anti-corruption reform program.

Speaking during Independence Day rites Thursday in Naga City east of Manila, Aquino denied his government was selective in investigating and prosecuting those involved in the scam.

Ombudsman Conchita Carpio Morales, who prosecutes state officials and employees involved in wrongdoing, filed the charges against the three senators last week, a year after the scam involving the development assistance fund was exposed.

A government audit last year showed that at least $141 million allocated from 2007 to 2009 was released to questionable aid groups and ghost projects that were identified by lawmakers as beneficiaries.

Napoles allegedly collaborated with lawmakers in obtaining the funds.

The 90-year-old Enrile was accused of receiving $3.94 million in kickbacks out of $7.9 million from a lawmakers' project fund called the Priority Development Assistance Fund. Enrile was the longtime defense secretary of the late dictator Ferdinand Marcos before he broke away from the strongman in 1986.

Estrada, a son of ousted President Joseph Estrada, allegedly received $4.2 million out of $6.4 million. Revilla allegedly got $5.1 million out of $11.9 million.