An eerie lull settled over Southeast Asia last week, broken only by the rumble of Polish-built trucks on Red in filtration routes and the steady thump of American bombs aimed at interdicting them. The lull was reflected in South Viet Nam by battle statistics: the Viet Cong and their North Vietnamese allies suffered only 456 dead in the previous week—the lowest toll since January 1965—and even when U.S. air cavalrymen surrounded three Red regiments near Bong Son last week, the bulk of the Communist force slipped furtively away. The enemy battalion that was finally trapped put up a good fight—but reluctantly (see following story). The Reds were saving their strength for the monsoon, waiting for the rain-rich thunderheads that hamper American air strikes. And they were doing a lot of their waiting in the sanctuary of neighboring, "neutral" Cambodia.
Of late, Prince Norodom Sihanouk has frankly admitted that Communist troops have been using Cambodia for "rest and recreation" between battles.
In April the Prince handed over seven tons of dried fish to a Viet Cong representative in a ceremony at Pnompenh's royal palace. Last week American officials in Saigon disclosed that U.S. troops near the town of Lo Go on the Cambodian border had received heavy weapons fire from Cambodian territory, and were ultimately forced to silence it with howitzer fire. Even more interesting evidence of Sihanouk's cooperation with the Communists was the discovery of a new infiltration route into South Viet Nam—a chain of truck roads, bicycle trails and rivers that provides transport for supplies moving north and east out of Cambodia to some of the most important fighting areas of South Viet Nam. It has come to be known as the "Sihanouk Trail."
The new route—a supplement to the maze of paths and roads leading south called the Ho Chi Minh Trail—was discovered by the Laotian air force, whose commander, Brigadier General Thao Ma, had been keeping a close eye on Cambodia since last September. About that time, Ma received reports of activity along the Se Kong River, a tributary of the Mekong. Near its banks could be heard the sound of blasting and rumble of heavy equipment in a region virtually empty of inhabitants. By early April, Ma's aviators could follow the trail for 60 miles from Cambodia to where it entered South Viet Nam. Last week TIME Correspondent Don Neff flew over the Sihanouk Trail in one of six Laotian T-28 fighter-bombers led by General Ma. His report: