RIYADH, Saudi Arabia (AP) _ The powerful allied ground assault has taken at least 18,000 Iraqi soldiers prisoner, but an Arab commander today dismissed fears that the large number of POWs would bog down the offensive.

Lt. Gen. Khalid bin Sultan, the Saudi commander of the joint Arab forces, said he was prepared to handle up to 100,000 prisoners, and anticipated no problems from mass surrenders.

Khalid, speaking at a briefing in Riyadh, put the number of Iraqi prisoners at 20,000, counting those taken before the ground offensive began.

A short time later, however, U.S. Marine Brig. Gen. Richard I. Neal said the allied had captured 18,000 POWs within the first 24 hours of the ground war alone. About 3,000 were captured before the invasion.

Officials did not detail where or how the prisoners were taken, but reports from the field indicated many surrendered without a fight and that many were front-line troops in southern Kuwait.

One British television crew in Kuwait filmed an apparently wounded POW kissing one of his captors on the forehead as two Saudi soldiers helped him to walk. Other POWs were shown seated or lying, some of them wounded.

Reporter Sandy Gall of Independent Television News, whose crew took the footage, described the surrender:

''It was an amazing sight ... The Saudis were jubilant and some of the Iraqis looked just as happy that their battle was over.''

Other television footage showed long lines of prisoners being marched across the desert past allied armaments.

A senior Pentagon official said today that reserve and National Guard military police units were delousing, feeding, bathing and clothing the prisoners and then transporting them to Saudi Arabia. ''We make them as comfortable as we possibly can,'' the source said. Facilities have been prepared for thousands of POWs.

U.S. military officials in Saudi Arabia have said they will not let mass surrenders hinder their assault into Kuwait and southern Iraq, and Khalid echoed those comments today.

But several Pentagon war planners said in Washington Sunday they were concerned that too many Iraqi prisoners could slow the allied advance by forcing troops to walk the POWs south to Saudi Arabia under armed guard.

''We've had so many dad-gummed POWs, we hope they don't all surrender at once,'' one official said.

Another described the policy that has led to the mass surrenders.

''It's a slap-and-hug technique, designed to give them a chance to give up with dignity,'' the Pentagon official said. ''Thousands of them are coming out of their holes.''

Under the strategy, front-line Iraqis were first pounded with heavy artillery, then aircraft equipped with loudspeakers flew over their bunkers with Arab speakers encouarging them ''to cease resistance,'' the official said. The Pentagon officials discussed the POW situation on condition of anonymity.

Many Iraqi prisoners and defectors reaching allied camps before the ground offensive appeared dazed and exhausted from extensive allied bombing raids. They told allied interrogators they had been receiving little food or water. Others appeared to be adequately nourished.

Maj. Rex Forney, MP deputy provost marshal for the Army's 101st Airborne Division, said the prisoners were to be put in cages at the forward base and held for at least a day before being moved to Saudi Arabia.

Forney said the allies hope to move the POWs in double-decker passenger buses and evacuate wounded prisoners by helicopter if available. But if Iraqi forces counterattack, the prisoners will have to walk south, he said.