As many as 12 journalists have been confirmed dead in a massacre of more than 21 people in the Philippines, the country’s National Union of Journalists reported on Monday.

The journalists were part of a convoy traveling to file candidacy papers for gubernatorial candidate and local mayor Esmael Mangudadatu in the southern province of Maguindanao, on Mindanao island.

According to local news sources, the convoy was intercepted by over 100 gunmen at a police checkpoint, and more than 50 people, including the wife and sister of the candidate, and a number of journalists were taken hostage.

Police searching for the hostages have discovered at least 21 bodies, including those of 12 journalists in the village of Masalay. News reports said that some of the victims had been decapitated and mutilated.

“This is a senseless slaughter and no words can be strong enough to condemn it,” said IPI Director David Dadge. “These were innocent civilians who were either carrying out a political campaign or reporting on its activity. It is the work of journalists to report on political campaigns on behalf of the public. By acting in this way these individuals have shown that they not only stand outside of democracy but also outside of humanity. We convey our heartfelt condolences to the families of the murdered journalists and the other victims of this atrocity, and our thoughts are with those who are still waiting for news of their loved ones.”

The central government of the Philippines has limited control over the predominantly Muslim province of Maguindanao, which has been wracked by clan-based violence in the past. Several local politicians and warlords are believed to maintain armed militias of their own, and clashes between factions are common.

Staff at a hotel in Tacurong City, where some of the journalists were staying, reported that two unknown men had asked them about the reporters’ whereabouts, and demanded a list of their names, according to media reports. The hotel refused to release the information. Three journalists, on learning of this, made the decision not to travel with the group.

According to a partial list of accompanying media personnel released by the would-be candidate, Esmael Mangudadatu, to the Philippine Daily Inquirer, the following news organizations were represented in the convoy:

Dadiangas Times
Forum
Today
UNTV
DZRH
Mindanao Inquirer
Manila Bulletin

A source at the Manila Bulletin confirmed to IPI that one of their reporters was among those killed.

In an official statement, the Bulletin said: “We particularly lament and condemn the killing of the media people, who were there to carry out their duties and responsibilities as newspapermen and radiomen, getting legitimate information for publication and broadcast. We are deeply saddened and we denounce this blow to press freedom, a major pillar of our democracy.”

Monday’s deaths bring to at least 15 the number of journalists murdered in the Philippines in 2009, making it deadlier for reporters, so far this year, than any other country in the world.

Since Philippine President Gloria Arroyo came to power in 2001, 67 journalists have been killed, according to IPI|s Death Watch.