The former cabinet minister had said on Tuesday that he had established contact with the groups which account for a large part of the Sunni rebels and were responsible for attacks against Iraqis and foreigners, including assassinations and kidnappings.
However, both the Islamic Army in Iraq and the Army of Mujahidin categorically denied on Wednesday any contacts between their leadership and former electricity minister Ayham al-Samarie.
In a joint statement posted on the internet, the two groups said they had not authorised anyone to meet al-Samarie or attend his press conference scheduled for next Friday.
Al-Samarie had told Aljazeera and the Associated Press from Baghdad that the two groups were ready to open talks with the Iraqi government aimed at eventually joining the political process.
The claim had appeared consistent with comments from a senior Shia legislator, Hummam Hammoudi, who told the AP last week the government had opened indirect channels of communication with some anti-US groups.
The contacts were "becoming more promising and they give us reason to continue", Hammoudi said without providing details.
Al-Samarie, an Illinois Institute of Technology graduate who holds dual US and Iraqi citizenship, said the two groups represent more than 50% of the "resistance".
He excluded al-Qaida in Iraq group which has carried out some of the bloodiest attacks and is headed by a non-Iraqi, Jordanian-born Abu Musab al-Zarqawi.
"Guns will not solve the problem. Guns never solved any problems; it's always politics that solves problems"
former Iraqi Electricity Minister
US military officials believe about 12,000 to 20,000 fighters, including supporters, make up the anti-US and anti-government rebellion.
Al-Samarie said he began contacting anti-government political leaders about five months ago. He did not meet any field commanders, he said, but would not name those he contacted or say who else joined in the meetings.
"Guns will not solve the problem. Guns never solved any problems; it's always politics that solves problems," he said. "How can they (the government) solve the problem without talking to the resistance? The resistance exists and everyone knows it exists."
Al-Samarie said he told the rebel leaders they had to "come out to the political arena".
"We told them that 'no one knows what you want'," he said, speaking in his home in an upscale Baghdad neighbourhood. "You say you want the occupier to leave Iraq but what do you want after that? You must have a
The rebel leaders agreed "that the time has come for them to come out", al-Samarie said.
US forces say major arms caches
have been unearthed recently
The Islamic Army in Iraq is a significant anti-government group that has claimed responsibility for attacks on US and Iraqi forces as recently as in the last two weeks.
The group, most active in Baghdad and the region directly to the south, generally avoids bombings.
Besides attacks against US forces, it has claimed responsibility for assassinations of Iraqi government officials and the killings of an Italian journalist and Pakistani contractors.
It released two French journalists in December 2004 after holding them for 124 days.
The Islamic Army in Iraq claims thousands in its ranks and says its members are predominantly Iraqi.
According to rebel statements, the group has at times collaborated with al-Qaida in Iraq network of al-Zarqawi and the Ansar al-Sunna Army.
Less is known about the Mujahidin Army, but it has claimed responsibility for scores of attacks, including the April downing of a helicopter carrying 11 civilians, among them six Americans, and the kidnapping of Indonesian journalists who were released unharmed in February.