About 1,000 journalists and activists marched to the Malacanang presidential palace [EPA]

A group of about 1,000 journalists and activists have held a protest march in the Philippines capital, calling on the government to ensure that all those behind last week's massacre on the southern island of Mindanao are brought to justice.

The protesters, clad mostly in black shirts and carrying a black mock coffin and placards, marched to the presidential palace, which had been ringed by barbed-wire and police, on Monday.

Media watchdogs have said that the mass killing on November 23 - which left 57 civilians, including at least 30 journalists, dead - was the world's deadliest single assault on journalists.

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In a statement that was read out at the rally, Norila Daud, the president of the Malaysia-based Confederation of Asean Journalists, appealed to Gloria Macapagal Arroyo, the Philippine president, to spare no effort in ensuring that all suspects are apprehended.

Cerge Remonde, a former radio broadcaster and spokesman for Arroyo was booed and heckled when he tried to assure the protesters that the government was doing everything to give justice to the victims.

In a statement read by Remonde to reporters after the rally, Arroyo said that the country must rededicate itself to "to freedom of the press, freedom of political expression, and freedom to vote free from fear of violence and intimidation".

"We must all join hands to strengthen our resolve that never again will rouge political leaders take the law into their hands and violate the law of the nation and the laws of God," she said.

The Belgium-based International Federation of Journalists (IFJ) on Friday wrote to Arroyo saying that 75 journalists had been killed during her eight years in office, even before last week's massacre in Maguindanao.

The IFJ said that only four convictions of the killers have been secured.

Suspect's denial

Andal Ampatuan Jr, a local mayor who was a member of Arroyo's coalition, has been charged with murder over the November 23 killings, with other members of his powerful clan named as suspects.

On Sunday, the Ampatuans held a news conference to again deny responsibility in the killings.

Andal Ampatuan Jr faces multiple charges over the Maguindanao massacre [Reuters]
Zaldy Ampatuan, the governor of a Muslim autonomous region that includes Maguindanao, said he and his father, who has also been linked to the slayings, were innocent.

"We have been prejudged," Ampatuan told reporters at the family home, where about 30 local mayors had gathered to show support.

Outside hundreds of followers rallied, waving placards that read: "They are not killers."

The killings took place after supporters and aides of Esmael Mangudadatu, a local politicians, were going to file papers for his candidature in elections for provincial governor next year.

Dozens of armed men stopped the group, abducting them before they were killed and buried them in mass graves on a nearby hill.

Mangudadatu's wife and sisters were among the dead.

The killings have overshadowed the start of the campaign period for next year's national elections, drawing worldwide condemnation.

It has also highlighted the violent factionalism that plagues the volatile region, and the deadly risks journalists take in covering it.

On the eve of the Tuesday deadline for politicians to file their candidacy papers for the elections, many of the would-be presidential candidates said there was a desperate need for change in the country's political system.

Source: Al Jazeera and agencies