Two journalists, Mir Nawab and Allah Noor, were shot dead Monday while returning home from covering a ceremony marking a truce agreement between the government and local militants.

A third colleague traveling with them was seriously wounded when unknown assailants ambushed a bus the journalists were riding.

The men, both natives of South Waziristan where the killings took place, were working for a number of Pakistani and foreign news media, including Japan's NHK, the Associated Press and the Voice of Germany.

Information Minister Sheikh Rashid Ahmed says both the government and a local journalists' association have petitioned Waziristani tribal leaders to help investigate the murders. "We are putting this case to the tribal jirga [council] ? and the journalist organization requested the tribal people to investigate and to arrest these culprits," he said.

Mr. Ahmed says police are also trying to discover the identities and motives of the killers.

Associates say the slain reporters had managed to photograph some suspected militants Monday and that they were targeted as a result.

Over the past year and a half, South Waziristan has seen off-and-on fighting between the Pakistani army and local militants.

The army has been tracking suspected terrorists and Afghan anti-government insurgents believed hiding along the border with Afghanistan.

While most of the tribal elders have cooperated with the government, some local militia leaders are opposed to the army's presence, which they see as representing the interest of foreign powers.

Local reports say pamphlets have circulated recently criticizing news coverage of the conflict.