South Korean forces in Iraq have been placed on alert and ordered to stay inside their barracks following an attack on their base, the Defense Ministry said Tuesday. «There are chances hostile forces will conduct additional strikes to maximize their terror effects,» Col. Won Tae-jae, a spokesman for the Joint Chiefs of Staff was quoted as saying by the Yonhap news agency. Four shells fell near the South Korean base outside the northern Iraqi town of Irbil on Monday in what South Korean media called the first attack on Seoul's forces in the country. There were no deaths or injuries and no arrests were made, AP reported. All off-base humanitarian and reconstruction work has been suspended and patrols and checkpoints around the base stepped-up, Won said. South Korea has deployed more than 3,000 troops to the training and reconstruction mission, codenamed Zaytun after the Arabic word for olive. Won said the shells were Russian-made rockets fired from vehicles and fell no closer than 200 meters (656 feet) from the base.