The Imperial Japanese Navy (IJN) had occupied Tulagi in May and had constructed a seaplane base nearby. Allied concern grew when, in early July, the IJN began constructing a large airfield at Lunga Point on nearby Guadalcanal—from such a base Japanese long-range bombers would threaten the sea lines of communication from the West Coast of the Americas to the populous East Coast of Australia. By August, the Japanese had about 900 naval troops on Tulagi and nearby islands and 2,800 personnel (2,200 being Korean forced laborers and trustees as well as Japanese construction specialists) on Guadalcanal. These bases would protect Japan's major base at Rabaul, threaten Allied supply and communication lines and establish a staging area for a planned offensive against Fiji, New Caledonia and Samoa ("Operation FS"). The Japanese planned to deploy 45 fighters and 60 bombers to Guadalcanal. In the overall strategy for 1942 these aircraft would provide air cover for Japanese naval forces advancing farther into the South Pacific.