The 41st moved from Hawaii and on 17 December arrived at Tarawa. Before the Group could mount its own offensive however, the rubble caused by the recent fighting had to be cleared away and the airstrips repaired. The uncomfortable climate, the temporary delay, and an outbreak of dengue fever and dysentery combined to make life miserable for the men of the 41st. Frequent Japanese nuisance raids added to the sense of helpless frustration. On 28 December, the 820th Squadron launched the Group's combat mission with an attack on the new enemy air facilities at Mili Atoll in the Marshall Islands. During the month of January 1944 the Group conducted 215 sorties against the Japanese positions in the Marshalls. Maloelap, Wotje, Mili, and Jaluit became familiar to the crews of the B-25s. Those islands contained air facilities from which the Japanese might interfere with the scheduled invasions of Kwajalein and Eniwetok set for February 1944. In low-level attacks, the medium bombers of the 41st effectively raked Japanese installations and shipping. The raids however, were made at a high cost for the unit. Enemy opposition, particularly over Maloelap, was stiff, and at times as many as 50 enemy fighters rose to challenge the Group's formations. Between 28 December and 12 February the Group lost 17 B-25s.