THE VIENTIANE MILITARY AIRPORT, NEXT TO A CIVILIAN AIRPORT, WAS DESTROYED YESTERDAY (SUNDAY) BY A SERIES OF EXPLOSIONS, DEALING A SERIOUS BLOW TO THE LAOTIAN AIR FORCE'S STRIKE POWER AGAINST THE COMMUNIST PATHET LAO TARGETS. ABOUT NINE T-28 FIGHTER BOMBERS -- WERE DESTROYED IN THE BLASTS AND THE FIRE WHICH FOLLOWED.

THE FIGHTER BOMBERS HAVE BEEN FLYING DAILY MISSIONS AGAINST THE SO-CALLED HO CHI MINH TRAIL, ALLEGED TO BE USED TO SEND MEN AND SUPPLIES FROM COMMUNIST NORTH VIETNAM THROUGH CENTRAL LAOS TO COMMUNIST-LED VIETCONG INSURGENTS IN SOUTH VIETNAM.

THE EXPLOSIONS FOLLOWED CLOSE ON THE HEELS OF A PATHET LAO WARNING THAT FURTHER AIR ATTACKS ON COMMUNIST-HELD AREAS WOULD BE MORE SEVERELY PUNISHED.

ALTHOUGH THE CAUSE OF THE EXPLOSIONS WAS NOT IMMEDIATELY KNOWN, IT WAS REPORTED THAT A MACHINE-GUN WAS HEARD TO GO OFF BEFORE THE EXPLOSIONS.

AMONG THE CRATERS AND DEBRIS LITTERING THE RUNWAY -- A MASS OF TWISTED METAL POINTING SKYWARDS -- WERE AIRCRAFT ENGINES, BURNED OUT PLANES AND HELICOPTERS. A MAIN MAINTENANCE HANGAR WITH EQUIPMENT AND SOLDIERS' BARRACKS WERE GUTTED. SEVERAL TRANSPORT AIRCRAFT WERE HIT BY EXPLODING BULLETS. THE DAMAGE WOULD HAVE BEEN GREATER IF THE AIRPORT'S AMMUNITION STORE HAD BLOWN UP.