The Geneva accords of 1954 that separated North and South Viet Nam stipulated the creation of a buffer zone between the two countries. No troops were to enter this so-called Demilitarized Zone, which averages three miles in width on either side of the Ben Hai River frontier. Hanoi has long regarded the DMZ as a convenient, protected freeway for infiltrating its soldiers into the South. Flagrant though that violation was, in recent months Hanoi has done far more: it has turned the DMZ into a giant staging area and mortar and artillery base for its buildup against the U.S. Marines facing the zone. In almost a month of continuous fighting just south of the DMZ, the Marines have been repeatedly attacked in force and increasingly hit by round-the-clock, all-too-accurate mortar, rocket and recoil-less-rifle fire originating from the DMZ.
Last week, by land, sea and air, the Marines and South Vietnamese hit back in a multipronged, 10,000-man operation, sweeping into the DMZ area south of the border in an effort to drive the North Vietnamese out of it. Five Marine battalions struck from the south toward their own besieged base of Con Thien. A South Vietnamese task force roared northward up Route 1 all the way to the river border, then divided and turned back to push the enemy southward. Due north of Con Thien, a Marine battalion helicoptered into the DMZ to hammer the North Vietnamese toward the Marines moving north. And in a spectacular amphibious and helicopter assault, two more Marine battalions scythed in from the South China Sea. Waiting to do battle were two North Vietnamese regiments in the DMZ itself and at least three or four enemy battalions operating south of the zone —some 6,000 Communist soldiers of the estimated 35,000 in the border area.
A Formidable Fleet. Operation Hickory began with the Marine drive from Cam Lo to relieve Con Thien, which has been under almost constant mortar attack since May 8. The terrain favored the dug-in enemy: a dense jungle tangle of banana trees, bamboo, betel-nut and breadfruit trees in which visibility was seldom more than 15 ft., and fields separated by 10-ft.-high hedgerows. One company was within a mile of Con Thien when it was pinned down by fire from the seemingly deserted village of Trung An. The North Vietnamese had built of logs, trees and dirt an astonishing network of 300 holes throughout Trung An, were so well burrowed that even the U.S. bombers' 1,000-pounders and napalm failed to root them out. The leathernecks called up big M48 tanks to break through the hedgerows and roll right up atop the enemy bunkers.