RIYADH, SAUDI ARABIA — RIYADH, Saudi Arabia -- U.S. forces stepped up yesterday the number and size of ground clashes by sending helicopters into Iraqi-held territory, destroying a bunker complex there and capturing more than 450 Iraqi soldiers.
While maintaining that they were following their campaign plan, U.S. commanders appeared to open a new phase by attacking && more distant targets and putting larger numbers of U.S. ground units into action. Air strikes increased in number, as commanders have said they would immediately before a major ground assault.
In one of the two major clashes yesterday, one U.S. soldier was killed and seven others were wounded. U.S. military spokesmen said the men were members of a company-size unit that 'D encountered Iraqi infantry, tanks and artillery north of the Saudi border.
U.S. forces involved in the action destroyed five Iraqi tanks and 20 artillery pieces and captured seven soldiers. Spokesmen said two armored U.S. vehicles were damaged by artillery fire.
Within 15 minutes of that clash, four U.S. helicopters crossed theSaudi border to attack an Iraqi bunker complex with rocket fire. Marine Brig. Gen. Richard I. Neal, the U.S. military spokesman, said that 450 to 500 Iraqis surrendered after the helicopters destroyed at least 13 bunkers.
As of last night, transport helicopters with U.S. soldiers acting as a security force were taking the Iraqis to a prisoner-of-war camp in Saudi Arabia. No estimates were available about the number of Iraqis killed or wounded during the attack.
The clashes marked an increase in the ferocity of ground battles and in the ambitions of U.S. forces. Each side in the conflict is trying to pinpoint the position of the other by peering over the border and sometimes crossing it. While U.S. troops have technically remained on the Saudi side of the border, military spokesmen acknowledge that the border is "broadening."
General Neal insisted that the possibility of Iraq's agreeing to a Soviet peace proposal was having no effect on morale. "The troops are ready to go," he said. "They're ready to go right now. They can go two weeks from now."
Gen. H. Norman Schwarzkopf, the allied commander, was described as "elated" by the news of the largest mass Iraqi surrender to date. But U.S. and allied officers express doubts that every unit will be as willing to lay down its arms.
"There are still a lot of Iraqi soldiers and a lot of Iraqi tanks and a lotof Iraqi artillery pieces and armored vehicles in the Kuwaiti theater of operations," said Lt. Gen. Thomas Kelly, operations director for the Joint Chiefs of Staff. "If we get a mission to move ground forces into Kuwait to defeat that army, I think we will be efficient . . . but it's not going to be a snap."
Judged by briefings with reporters, commanders are torn between satisfaction with the results of five weeks of air strikes and concern about the capabilities of Iraq's remaining ground forces.
Officers say that "a substantial number" of units, including most of the elite Republican Guards, appear willing to fight pitched ground battles. They discount reports that significant numbers of the Republican Guards are deserting and heading north into Iraq, describing the numbers involved as "a trickle."
Rear Adm. Mike McConnell, intelligence director for the Joint Chiefs of Staff, said that the Iraqi military "is still an effective fighting force in the sense that command and control still exists and there are still lots of tanks and soldiers in the field."
There is growing evidence that many Iraqi units intend to remain where they are even if U.S. forces begin a ground campaign. Officers say they are mystified that Iraq's army, equipped to fight large, fluid battles, shows no sign of getting ready to move, except to fall back to other prepared defensive positions.
Iraq could be waiting for weather conditions to change in its favor. Sandstorms typical in late winter could hamper allied helicopters and aircraft needed to support ground forces, while Iraq could move its forces with less fear of air attacks.
"I just can't believe [Saddam Hussein is] going to leave his units there and make us take out each one," a senior U.S. officer said. "But we have enough bombs to do that."
Cultural differences may complicate efforts by U.S. commanders comprehend the thinking of Iraq's leadership. During its eight-year war with Iran, in which more than a half-million Iraqis may have been killed or wounded, Iraq's army suffered 10,000 dead in a single day, yet never paused, according to a Pentagon official.
If a full-scale ground war begins, U.S. forces would depend on "speed, shock and firepower," moving the largest possible number of tanks at the fastest possible speed, another officer said. "You don't have to destroy every one of his soldiers and every one his bunkers," he said. "We want to roll as quickly as we can."
Some of the most recent clashes appeared to be tests of that strategy. On Tuesday, U.S. forces targeted a depot more than 50 miles north of the Saudi border and containing more than 300 vehicles. At least 28 tanks were said to be have been destroyed.
Allied aircraft meanwhile flew 2,900 missions in the latest 24-hour period, the highest daily total in more than a week. More than 900 missions were against targets in and around Kuwait.
B-52 bombers flew over western Iraq to bomb the suspected launch site for the Scud missile fired Tuesday against Israel. Pilots reported seeing large explosions after dropping their bombs.
U.S. casualties
Here are the names of U.S. servicemen the Pentagon has listedas fatalities or missing in action since Feb. 6.
KILLED IN ACTION:
Air Force Capt. Douglas L. Bradt, 29, Houston, Texas
L Air Force Capt. Paul R. Eichenlaub II, 29, Bentonville, Ark.
Army Spc. Jeffrey T. Middleton, 26
Army Pfc. Robert D. Talley, 18, Newark, N.J.
MISSING IN ACTION:
Navy Lt. Patrick K. Connor, 25, Virginia Beach, Va.
Navy Lt. Cmdr. Barry T. Cooke, 35
Navy Lt. Robert J. Dwyer, 32
Air Force Capt. Stephen Richard Phillis, 30
Marine Capt. Russell A. C. Sanborn, 27, Havelock, N.C.
Air Force 1st Lt. Robert James Sweet, 24
PRISONER OF WAR:
5) Air Force Lt. Col. Jeffrey D. Fox, 39