Nasiriyah, Iraq ? A thirsty Iraqi mimed drinking from a bottle. A U.S. Marine shook his canteen to show it was empty.

Many Iraqis at a key crossroads in this southern city greet Marines with a thumbs-up — meaning thanks for coming — followed by an outstretched hand begging for food or water.

A young boy looked at the Marines and said something barely understandable that turned out to be an English word — chocolate. A man shouted “Good, Bush” as he drove past.

It’s hard to tell whether the appreciation is genuine, or just a way of playing it safe with the new masters. But Lance Cpl. Brian Cole, 20, of Kansas City, Kan., was bowled over by the 7-year-old girl who handed him a Christmas card with this painstakingly written text: “Thank you for liberate us. And thank you for help us. You are a great army.”

“That made my day, after sitting out in the heat all day. It made it seem worthwhile,” Cole said.

Help is on the way, U.S. Central Command promised Saturday. But far from its supply base, Echo company of the 15th Marine Expeditionary Unit can barely cover its own needs — let alone those of Iraqis.

“They are still asking us for water but not as bad anymore because they realize we don’t have any,” said 22-year-old Lance Cpl. Garret Amerine of Laguna Niguel, Calif.

By day, the hot dusty crossroads bustled with activity — women in black robes carrying bundles on their heads, children in brightly colored clothing, donkeys and horses pulling carts. On Saturday, Marines allowed cars, buses and trucks to cross as well, after searching them for bombs.

Now that traffic is moving again, buses and trucks are delivering tomatoes and other produce. A battered blue pickup truck carries two cows. Other trucks were loaded with brush for firewood.

But after nightfall, all traffic stops.

“It is too dangerous to come at night. It is too dangerous to approach any army at night,” said Akeel Abdullah, a 22-year-old unemployed English teacher.