They will be reinforced by another 800 soldiers in early November, defense officials said.

The South Korean contingent, the third largest in the US-led coalition in Iraq, is taking up positions in Arbil, a Kurdish-controlled northern town. It will start operating from next month, the ministry said in a statement.

The announcement followed a media blackout on the troop deployment which began with a secret airlift on August 3, preceded by protest rallies by South Korean anti-war activists.

Seoul had defended the ban on media access, citing the security of its forces and civilians in Iraq since the execution of a South Korean translator by Islamic militants in June.

Abductors beheaded Kim Sun-Il after President Roh Moo-Hyun rejected their demand that Seoul cancel its plan to send troops to Iraq.

The media has broadly complied with the ban on reporting the deployment, although editorials have criticized the restrictions and one leading newspaper said it felt "ashamed" at bowing to the curbs.

Parliament approved the dispatch of troops in February but stipulated that they would engage in relief and reconstruction work only and avoid combat.

But a group calling itself Ashap Rayat Sud (Black Banners), affiliated with the Islamic militant organization Ansar al-Sunna, sent a videotape to Seoul last month, threatening to attack South Korean troops and citizens in retaliation.

Ansar al-Sunna has claimed responsibility for many attacks, including a suicide bombing which killed at least 105 in Arbil in February.

The defense ministry said its troops reached Arbil by crossing a 1,115-kilometer (690-mile)-long highway from Kuwait under heavy security cover.

Television footage, belatedly released by the ministry Wednesday, showed troops moving in a convoy of trucks and armored vehicles backed by US helicopters.

The troops sometimes had to detour or detonate explosives found in their path to Arbil but non one was hurt.

The footage also showed South Korean troops in desert-colored camouflage and wearing masks to protect against dust, setting up a large satellite dish against the backdrop of low-lying barracks.

Pictures distributed by the ministry showed rows of jeeps, trucks whose sides were shielded with armor and flatbed trucks carrying armored personnel carriers moving through the streets of Arbil.