Iraqi troops, backed by US advisers, captured a senior leader in a Mahdi Army offshoot group with links to Iran during a raid in Baghdad.

The senior leader of the Promised Day Brigade was detained in northern Baghdad, with the help of intelligence gathered from both US and Iraq security forces.

The Promised Day Brigade commander, who was not identified, was "believed to be facilitating the distribution of weapons and funding to PDB [Promised Day Brigade] attack groups throughout Baghdad," the US military said in a press release. "Attack groups then use the weapons and funding to conduct deadly acts of violence against civilians and security forces in Iraq."

The US military said the commander "is allegedly tied to PDB [Promised Day Brigade] leaders operating from safe havens in Iran."

The Promised Day Brigade was formed by anti-American Shia leader Muqtada al Sadr during the summer of 2008 after he announced he would disband the Mahdi Army and formed a small, secretive military arm to fight Coalition forces in June. The group has not been linked to any major attacks since its formation last summer.