BAGHDAD (AFP) -- Iraq Prime Minister Nuri al-Maliki Saturday embarked on his first trip abroad to garner support for his much-touted peace plan that has been rejected by the Sunni leaders and rebels.

The U.S. military, meanwhile, said Friday it had ordered a probe into the alleged killing of four Iraqi civilians by U.S. soldiers south of Baghdad last week, the latest in a string of such investigations.

And at least 14 people were killed in a string of attacks across the country, as Al-Qaeda leader Osama bin Laden warned that the jihad or holy war could continue despite the killing of the network's local leader Abu Musab al-Zarqawi three weeks ago.

Maliki left Saturday for Saudi Arabia, then the United Arab Emirates and Kuwait "to meet their leaders to discuss the national reconciliation plan," said Minister of State for National Dialogue Akram al-Hakim.

Maliki announced a national reconciliation plan last week in a bid to stem the Shiite-Sunni violence ravaging Iraq. The plan, however, has already been rejected by a number of Sunni Arab leaders and rebel groups.

It is felt that Maliki's tour may help influence the former elite community of Sunni Arabs as many of its leaders have close ties with the oil-rich Arab states of the Gulf. Iraq's influential Sunni Muslim Scholars Association leader Muthana Hareth al-Dhari dismissed Maliki's plan as little more than "a campaign of public relations for the government", adding it was "meaningless because he has excluded everyone."

He said it also aimed to encourage die-hard Sunni Arab parties like his own which refuse to accept the rise to power of the long-oppressed Shiites, to abandon their sympathies for armed struggle and join the political process.

Maliki has said he would only pardon those detainees held in US and Iraqi prisons who have committed no violent crimes and stressed there would be no amnesty to those who killed foreign troops, journalists or innocent Iraqis.

More than 2,500 detainees have been freed this month from US and Iraqi prisons as part of the plan.

Maliki said he had been contacted by insurgent groups willing to lay down their weapons and that he would engage them in dialogue directly or through other officials.

The announcement was hailed by state-owned Iraqiya television and the government-owned Al-Sabah newspaper.

They even named the purported insurgent groups which approached Maliki and claimed that tribal leaders from the rebel stronghold of Ramadi in Al-Anbar province of western Iraq were acting as go-betweens.

But Dhari said: "Neither the principal armed groups of resistance nor political organizations like ours have accepted this plan which ignores a timetable for the withdrawal of (foreign) troops. "Nobody knows the so-called organizations mentioned in the government mouthpiece Al-Sabah, and the armed groups mentioned are also unknown."

Dhari said the main Sunni groups which rejected the proposal were the Brigades of 1920 Revolution, the Rashedeen Army, Islamic Movement of Iraqi Mujahedeen, United Iraqi Jihadist People, and Jaish al-Mujahedeen.

"We are not concerned by this initiative as it does not address the main problem of occupation and also the militias," said the Brigades of 1920 Revolution in a statement.

Jaish al-Mujahedeen also discarded the proposal saying it will not "dirty its hands... by shaking the hands of those who are with the occupiers (U.S.-led forces)".

On Friday, an Internet-posted voice message purported to be from bin Laden paid tribute to Zarqawi who was killed in a U.S. air strike on June 7.

"We will keep up our fight to bleed your money dry, kill your men and so that (your forces) go home defeated, as we defeated you in Somalia," bin Laden told U.S. President George W. Bush.

"The banner of jihad has not fallen. It will be picked up by another lion of Islam," he said in the message, which the CIA said was the voice of bin Laden.