Speaking to journalists on Tuesday, Paul Bremer said the threat posed by Ansar al-Islam to US-led occupation is genuine, adding that possibly over 200 fighters may have slipped back into Iraq.
“It is a serious threat and one we are trying to deal with. There are other foreign fighters, some may characterise as terrorists, here also,” he said.
The chief administrator's comments run counter to more usual US claims that resistance in Iraq is coming from Baathist die-hards and supporters of the former government.
But Bremer also claimed that Ansar al-Islam is affiliated to Usama Bin Ladin’s al-Qaida network and suggested that other groups with grudges against the US were seeking to enter occupied Iraq.
Last April, US-led forces conducted a devastating air and ground assault to wipe out the Islamist group’s enclave in northern Iraq.
It is believed that over 800 men and teenagers were killed during an attack that obliterated 16 villages, according to AFP. Many of those died belonged to other Islamist groups which had stayed neutral in the US-led invasion of Iraq.
Ansar al-Islam is one of a number of Sunni Islamist groups based in the majority Kurdish northern provinces of Iraq.
Until the April raids, the group’s bases were in and around the villages of Biyara and Tawila, which lie northeast of the town of Halabja in the Hawraman region of Sulaimaniya province bordering Iran.
Ansar al-Islam was formed in September 2001, initially under the name of Jund al-Islam - though its constituent factions have existed for several years.
Despite repeated accusations by the Patriotic Union of Kurdistan, the existence of any links with al-Qaida and Usama Bin Ladin is unknown and unproven, according to Human Rights Watch.
The group has declared war against secular and other political parties in Iraqi Kurdistan deemed to have deviated from Islamic values.
Najm al-Din Faraj Ahmad, known as Mulla Fatih Krekar, became its leader in December 2001 and is currently claiming asylum in Norway.