Ethnic Kurds are helping members of the Islamic State group in the battle for the key Syrian Kurdish town of Kobani, sharing their knowledge of the local terrain and language with the extremists, according to Iraqi and Kurdish officials.

It is not clear how many Kurds are aiding the estimated 3,000 Islamic State militants in the Kobani area -- and fighting against their own Kurdish brethren -- but activists say they are playing a major role in the 7-week-old conflict near the Turkish border.

A top military commander for the extremists in the town is an Iraqi Kurd, known by the nom de guerre of Abu Khattab al-Kurdi, helping them in the battle against fellow Kurds.

Officials with the main Syrian Kurdish force known as the People's Protection Units, or YPG, say they became aware of the Kurds among the mostly Sunni Muslim extremists early in the fighting.

As Kurdish fighters were defending the nearby Syrian village of Shiran in September, two Kurdish men with different accents and wearing YPG uniforms infiltrated their ranks, Kurdish officials said. Upon questioning, however, they were captured and admitted to fighting for the Islamic State group, the officials added.

Iraqi and Kurdish officials say many of the Kurdish fighters with the Islamic State group are from the northeastern Iraqi town of Halabja, which was bombed with chemical weapons by Saddam Hussein's forces in 1988, killing some 5,000 people.

Shorsh Hassan, a YPG spokesman in Kobani, said although most of the Kurdish jihadi fighters come from Iraq, some are from Syrian regions such as Kobani, Afrin and Jazeera. He added that the number of Syrian Kurds is small compared with the dozens of Iraqis fighting with the IS group.

"The fighter who is from Kobani is not like someone who hails from Chechnya with no idea about tracks and roads," Hassan said.

Thousands of militants from all over the world -- including north Africans, Asians and some Westerners -- have traveled to Syria and Iraq to join the ranks of the Islamic State group. Turkish nationals are among them, but it is unknown if any are fighting in Kobani.

Hassan said many of the Iraqi fighters were from Halabja, including al-Kurdi. Websites affiliated with the Islamic State group recently published several photographs of the young, bearded man, including some of him wearing the traditional Kurdish garb of baggy pants, and others of him standing in front of Kurds killed in Kobani.

In Baghdad, an Iraqi security official said al-Kurdi was a member of Ansar al-Islam, a Sunni militant group with ties to Abu Musab al-Zarqawi, the late leader of Al Qaeda in Iraq, who was active in the early 2000s. Al-Kurdi later joined the Islamic State group, the official said.

The Iraqi official said al-Kurdi is also from Halabja and is wanted by Iraqi authorities. He refused to give the man's real name when pressed by The Associated Press.

"Our latest information is that he is in Syria fighting in the Kobani area. He is an expert in mountainous areas," the Iraqi official said, speaking on condition of anonymity because he was not authorized to talk to the media.

"He is commanding the Kurdish group within Daesh because he is a Kurd," he added, using an Arabic acronym for the Islamic State group.

Halabja was known as a secular village and the home of Abdullah Goran, one of the best-known Kurdish poets in the 20th century and a member of the Iraqi Communist Party. But in the past three decades, Muslim preachers have become active and have turned it into one of Iraqi Kurdistan's most religiously conservative areas.

Still, most of the Kurds are moderate and secular-leaning Muslims.

Many Kurds in Iraq were stunned when they learned that Kiwan Mohammed, the 25-year-old goalkeeper of Halabja's soccer team, was killed last month in Syria while fighting for the Islamic State group in Kobani. Mohammed was identified by jihadi websites as Abu Walid al-Kurdi.

Dana Jalal, an Iraqi journalist who follows jihadi groups, said the Iraqi athlete left Syria in July 2013 and had not been heard of until his death.

Some 70 Iraqi Kurds, mostly from Halabja, went to fight in Syria with the Islamic State group, Jalal said. Most go through Turkey where they say they are going for tourism, but theu then they cross into Syria, and "some even take their wives with them," Jalal added.

Nawaf Khalil, the Europe-based spokesman for Syria's powerful Kurdish Democratic Union Party, said Kurdish fighters within the Islamic State group are invaluable in the Kobani battle because they know the geography, as well as the language and the mentality of fellow Kurds.

"A main part of their work is tapping (electronic surveillance) and intelligence-gathering. They might be also using some from the Kobani area to benefit from the geographical knowledge of the area," he said.

Mustafa Bali, a Kurdish activist in Kobani, said that by having Kurdish fighters, Islamic State extremists are trying to win the hearts and minds of Syrian Kurds in the area.

"Daesh is trying to tell the people of Kobani that it does not consider them enemies and its fighters include Kurds," Bali said.