By Jim Muir
BBC Middle East correspondent
A pocket of militant Islamic extremists, believed to be linked to Osama Bin Laden's al-Qaeda movement, is causing havoc in the Kurdish area of northern Iraq.
The presence of the violently anti-American group, known as the Ansar al-Islam (Partisans of Islam), is likely to attract increasing attention as US moves to overthrow Saddam Hussein's Iraqi regime gather pace.
A number of Washington's regional adversaries - including both Baghdad and Iran - appear to have a finger in the Ansar pie.
The Ansar are largely made up of Iraqi Kurds belonging to several radical Islamic groups which merged late last year.
They control a string of villages in the plains and mountains between the town of Halabja and the mountain ridge which marks Iraq's border with Iran.
But many of the Ansar's Kurdish members are believed to have returned from Afghanistan, where they had gone for training and to wage jihad (Holy War) alongside al-Qaeda and the Taliban.
Kurdish leaders who run the rest of Iraqi Kurdistan, and who have suffered heavily at the Ansar's hands, say that at least 20 or 30 Arabs linked to al-Qaeda have also come from Afghanistan to join the Islamist pocket.
'Iraq's Tora Bora'
The area has been dubbed "Iraq's Tora Bora" by some locals after the al-Qaeda stronghold in Afghanistan.
The worst atrocity occurred in the village of Khela Hama, near Halabja, which was overrun by radical Islamic fighters last year.
Kurdish forces have suffered losses at the hands of Ansar.
They captured and massacred 42 Peshmerga guerrillas from the Patriotic Union of Kurdistan (PUK), which controls the eastern half of Iraqi Kurdistan.
Some of the victims' hands were tied behind their backs when they died. The aftermath was filmed by the Ansar themselves, only to have the tape captured in a PUK counter-attack.
Since then, clashes with the PUK have continued. On 4 July, Ansar militants attacked PUK positions and killed eight Peshmergas, though the attack was beaten back.
Exactly who is involved with the Ansar and in what way is not clear.
The PUK leader, Jalal Talabani, says the one certain thing is that they had ties with al-Qaeda and Afghanistan:
"Many of them were trained there, and there are now about 20 to 30 Arabs who are trained from Afghanistan and who also came here to Kurdistan, and are now with them. Even their leaders are from these Arabs."
One of those leaders is Abu Wa'il, a former Iraqi army officer.
Shadowy connections
A captured Iraqi intelligence officer of 20 years' standing, Abu Iman al-Baghdadi, who is held by the PUK, said Abu Wa'il is actively manipulating the Ansar on behalf of Iraqi intelligence.
Abu Iman al-Baghdadi: "Some of Ansar trained in Iraq"
"I was captured by the Kurds after Iraqi intelligence sent me to check what was happening with Abu Wa'il, following rumours that he'd been captured and handed over the CIA," al-Baghdadi said.
He added that Baghdad smuggles arms to the Ansar through the Kurdish area, and is using the group to make problems for the PUK, one of the opposition factions ranged against Saddam Hussein.
"The Ansar's basic allegiance is to al-Qaeda, but some of them were trained in Iraq and went Afghanistan," he said, interviewed in a Kurdish prison.
"When the Americans attacked, they came here through Iran. Iraq is supporting them and using them to carry out attacks."
But Kurdish sources also believe that Iran is arming and training Ansar members, despite Tehran's denials. Ansar wounded are also said to have been treated in Iranian hospitals.
"The Iranian Government always plans to make Islamic security along its border with Kurdistan. Iran is also using these Islamic groups as a pressure card on the secular groups in Kurdistan," says Shwar Mohammad, editor of the Kurdish weekly Hawlati and one of the few people to have interviewed the Ansar leader Mullah Krekar.
Iranian links
Iran has for some time had a strong relationship with the PUK, but is said to be displeased with the Kurdish groups' secret discussions with the Americans about plans to overthrow Saddam Hussein.
Mullah Krekar: "Democracy is rejected by Islam"
As was the case with the Taleban in Afghanistan, there is no love lost between Tehran and the Iraqi ruler.
But Iran equally has no desire to see Saddam displaced by an American-led regime change that would put US forces on Iran's western flank.
The Ansar leader, Mullah Krekar - his real name is Najmuddin Faraj - has citizenship in Norway where he once sought refuge.
He left Iraqi Kurdistan recently, supposedly to raise funds in Norway, but the authorities there say he has not turned up.
So his current whereabouts are a mystery.
A stern young man with a black beard and black-and-white turban, he gave Hawlati's Shwan Mohammad a stark vision of the brand of Islam to which he and his followers subscribe.
"Democracy is based on four principles which are rejected by Islam," he said. "As far as Islam is concerned, democracy, from beginning to end, is heresy."
If both Iraq and Iran are indeed involved with the Ansar in one way or another, that would make strange bedfellows of the two neighbours who fought a long and bloody war through most of the 1980s and remain on difficult terms.