Al-Qaeda in Iraq is a shadowy group that was once allegedly led by Jordanian militant Abu Musab al-Zarqawi. Zarqawi was reportedly killed in June 2006.
According to US government and military officials, the group was then led by Ayyub al-Masri, who was killed along with Abu Omar al-Baghdadi - another leader of the group - in a joint Iraqi-US operation in Salahuddin province in April 2010.
Al-Qaeda in Iraq has been blamed for some of the deadliest terrorist attacks in the country since the US-led invasion in March 2003.
Iraqi security forces have arrested six members of al-Qaeda-inspired Islamic State of Iraq network as they were planning to target Shia Muslim processions on Arbaeen, which marks the 40th day after the martyrdom anniversary of Imam Hussein (PBUH).
Police sources, speaking on condition of anonymity, said on Tuesday that the terrorists were detained during sweep operations in the city of Karbala, located about 100 kilometers (62 miles) southwest of Baghdad, the Aswat al-Iraq news agency reported.
Staff Lieutenant General Othman al-Ghanimi, commander of Al-Furat al-Awsat operations command which covers the Karbala area, said on Sunday that 66 al-Qaeda members were arrested in Karbala province.
About 35,000 security soldiers have reportedly been deployed to the city of Karbala to provide security for the Arbaeen ceremonies, which fall on January 3.