The Ansar al-Sunnah Army (search) has emerged from its roots as a little known militant group operating in northern Iraq to become the country's deadliest terror network, capable of carrying out spectacular strikes like last week's homicide bombing at a U.S. base and virtually eclipsing Al Qaeda's cell in the war-torn nation.

Unlike Al Qaeda (search), Ansar al-Sunnah is believed to be made up mainly of Iraqis, and its apparent strategy of targeting only Americans and those viewed as collaborating with them — Iraqi security forces and Kurds — may have increased its support, in contrast to other groups that have hit more clearly Iraqi civilian targets.

Nearly five months after the collapse of Saddam Hussein's (search) regime in April 2003, Ansar al-Sunnah's first statement surfaced on the Internet, pronouncing itself "a group of jihadists, scholars, and political and military experts" dedicated to creating an Islamic state in Iraq.

The statement was signed by the group's "emir," or leader, the previously unknown Abu Abdullah al-Hassan Ibn Mahmoud (search).

Since then, it has carried out numerous bombings and attacks, particularly in northern Iraq — and shown its ruthlessness with the slaying in August of 12 kidnapped Nepalese construction workers, releasing video showing their deaths. In its deadliest operation, Ansar al-Sunnah claimed responsibility for Feb. 1 homicide bombings against two Kurdish political parties in Irbil, killing 109 people.

In the Irbil attack, the group slipped bombers into the Kurdish party offices during celebrations to set off their explosives. Tuesday's attack on U.S. forces at Mosul showed even greater sophistication and planning: a bomber — possibly in an Iraqi military uniform — entered a dining tent on the heavily guarded American base and detonated the blast during lunch, killing 22 people, mostly American soldiers and civilians.

Now the group is warning Iraqis not to participate in crucial Jan. 30 elections, promising to attack polling stations.

But who exactly is behind Ansar al-Sunnah and how it was formed remains a mystery. Some experts believe the group splintered from Ansar al-Islam, an Al Qaeda-linked group established in September 2001.

Ansar al-Islam was founded by Mullah Krekar, who has been living as a refugee in Norway since 1991. The group vowed to set up a conservative Islamic state in northern Iraq, and its members have trained in Afghanistan and provided safe haven to Al Qaeda members fleeing the U.S. invasion there.

The offshoot group may have changed its name to Ansar al-Sunnah — Arabic for "supporters of the sunnah," of the traditions of Prophet Muhammad — as an attempt to appeal to Iraq's minority Sunni Arabs, experts suggest.

There is nothing to corroborate this theory except that the group mainly operates in northern Iraq where Ansar al-Islam is based.

Mohammed Salah, a Cairo-based expert on Islamic militancy, said research indicates that the Ansar al-Sunnah Army was established by a mix of various Sunni Muslim anti-occupation factions that came together after the end of the war.

They chose the name Ansar al-Sunnah (loosely translated as "supporters of the traditions of Prophet Muhammad") to distinguish the Sunni group from Shiite militias, Salah said.

The group now seems to include nationalists and other secular people opposed to the U.S. presence in Iraq who are not typical religious fundamentalists or extremists but who "chose the cover of Islam as a propaganda that sells well."

The group seeks an Islamic government and Islamic law in Iraq, stressing its opposition to democracy, which it says replaces God's rightful rule with that of man.

"We believe democracy is an atheist call that idolizes human beings," says a manifesto detailing Ansar al-Sunnah's ideology.

The group's Web site, which also has a Kurdish page, features videos of aspiring homicide bombers and footage of attacks and beheadings. Statements on the site dismiss Iraqi politicians as "American puppets and agents" and condemns "collaborators" in the U.S.-trained Iraqi army and police.

Among its targets have been Kurds, with the group claiming to be behind the kidnapping and beheading of several Kurdish politicians. The Kurdish parties of northern Iraq are archrivals of Krekar's Ansar al-Islam.

On its Web site, Ansar al-Sunnah also denounces the upcoming elections, calling on Muslims to shun the ballot boxes as "centers of atheism" and adding: "We warn everyone that the Mujahedeen will be attacking polling stations."

In November, Ansar al-Sunnah said it collaborated in two attacks with other radical organizations — Al Qaeda in Iraq, led by Jordanian Abu Musab al-Zarqawi, and the Islamic Army in Iraq. However, similar announcements have not been repeated since.

Still, it remains unclear whether Ansar al-Sunnah is linked to Usama bin Laden's network, or whether it is actually competing with it.

U.S. officials have said Ansar al-Islam, its alleged parent group, is believed linked to al-Zarqawi.

But while al-Zarqawi's Tawhid and Jihad group in October declared allegiance to bin Laden, changing its name to Al Qaeda in Iraq, no such announcement was made by Ansar al-Sunnah.

Singapore-based terrorism expert Rohan Gunaratna said Zarqawi's group allied itself to Al Qaeda because it seems to be expanding its recruitment efforts to the entire Middle East and Europe as opposed to Ansar al-Sunnah's "exclusive Iraqi focus."

While Ansar al-Sunnah's targets have mainly been coalition troops, Kurds and "collaborators" with the coalition, Al Qaeda's operations included attacks that killed many Iraqi civilians, he said.

"Ansar al-Sunnah Army seems more organized and it's generated more support than Al Qaeda in Iraq ... Al Qaeda's attacks have often alienated significant support," Gunaratna said.

With or without Al Qaeda, it looks like Ansar al-Sunnah is here to stay.

"I think Ansar al-Sunnah will, as an organization, last longer and will enjoy a broader base of support than Al Qaeda in Iraq," Gunaratna said.