 Construction of defensive localities sited in all-round defence with interlocking arcs of fire began almost immediately, although such operations were confined to the reverse slopes during the day due to artillery and mortar fire which made such operations hazardous.Patrolling and ambushing by both sides also began in order to prevent the other from gaining control of no man's land.The 1st Commonwealth Division, which included British, Australian, Canadian, New Zealand and Indian troops, subsequently occupied part of the Jamestown Line—a UN defensive position which extended across central Korea—in the US I Corps sector on the US Eighth Army's left flank.