Marine 1st Lt. James Uwins was about to take a nap after days of running supplies to forces just south of Nasiriyah when he saw traces of sporadic gunfire.

The ambush that followed on March 25 lasted 90 minutes, wounding 31 troops from the 2nd Battalion, 8th Marine Regiment. No Americans were killed.

"There was no clue as to the specific direction the fire was coming from," Uwins said Wednesday at the Landstuhl Regional Medical Center where he was being treated. "But we knew it was coming from three sides on our perimeter."

The group of Marines, based in Camp Lejeune, N.C., had just completed a delivery of arms, ammunition and food to Marines on the front lines, at a bridgehead outside of Nasiriyah, when they stopped to rest at an abandoned roadside gas station.

When the attack started, Uwins dove for the cover of his Humvee. Shrapnel caught him in both legs as rockets and rocket-propelled grenades exploded around him.

Marine Gunnery Sgt. Bill Hale was blown 25 feet into the air, but recovered quickly, sending teams of Marines to clear concrete walls around the gas station.

"Adrenalin kicked," said Hale, from a wheelchair at Landstuhl, where he was being treated for a herniated disc, a dislocated right knee and nerve damage that has cut feeling in his toes.

"You have to be on 100 percent alert," said Uwins, 26, of South Pasadena, Calif. "You're not under a constant ambush all the time, but the fact that (the threat) is always there creates this high-level tension."

Hale, a veteran of the 1991 Gulf War, said the contrast between that conflict and this latest military action was striking.

In the earlier war, prompted by Iraq's invasion of Kuwait, the Kuwaiti people welcomed U.S. forces, he said. Now, there's no way to tell an Iraqi civilian from a soldier, and the Iraqi resistance has unmistakably slowed the coalition forces' advance, he said.

"In Nasiriyah, this battle was only supposed to last six hours. But then we were fighting five days straight, 24 hours a day," said Hale, 35, of Pennsauken, N.J.

The Marines are among 221 combat wounded who have been treated at Landstuhl, in southwestern Germany, since the war began March 19. Ninety-four troops and a civilian remain at the hospital, the American military's largest outside the United States, Landstuhl spokeswoman Marie Shaw said.