US forces in Iraq have captured a man thought to be the number three in Ansar al-Islam - an extremist Muslim group suspected of links with the al-Qaeda network, a senior US defence official says.
The man, Aso Hawleri, was picked up by members of the US army's 101 Airborne Division in the northern Iraqi town of Mosul on Friday, the official says.
Ansar al-Islam may have been involved in recent attacks on US troops
If his arrest is confirmed, Hawleri would is the most senior member of the group to be in US custody - a big catch as the official put it.
It is not known precisely what role, if any, Ansar al-Islam has played in the recent spate of guerrilla style attacks on the US-led forces in Baghdad.
Its strongholds were in northern Iraq, but a top US commander said in August that members of the group had headed towards the Baghdad area.
The Pentagon officials said it was hoped that at the very least the new detainee would have information on what links there are between the group and al-Qaeda.