A U.S. Army parachutist of the  173rd Airborne Brigade guards an airfield seized by U.S. troops in northern Iraq.

BASHUR, Iraq -- The U.S. military Thursday began airlifting troops, tanks and equipment for the U.S. Army's 1st Infantry Division into northern Iraq after about 1,000 paratroopers secured a key airfield in the country's Kurdish-controlled zone.  Paratroopers from the Army's 173rd Airborne Brigade parachuted under cover of darkness into the area, which U.S. military officials described as "semi-permissive," meaning it was not hostile.  Securing the airfield also will open the way for humanitarian efforts to begin in the north.  As the trucks lumbered past blasted buildings on the Iraq-Kuwait border, an Iraqi boy about 10 pointed to his mouth and shouted "Eat, eat!"  After days of fierce fighting that shut down the city of Umm Qasr, Iraqi youths cheered and swarmed British troops as they handed out yellow meal packets and bottles of water Wednesday. The troops, already in the city, were not part of the aid convoy.

"Umm Qasr is now secure - as a port and as a town," said Brig. Jim Dutton of the Royal Marines. 

The town's deepwater port is needed for any relief effort. 

Plans to bring supplies to Iraqi civilians had been on hold for days because of fighting across southern Iraq. On Tuesday, U.N. Secretary-General Kofi Annan warned U.S. national security adviser Condoleezza Rice that the United States is legally responsible for providing relief aid. 

White House spokesman Ari Fleischer blamed Saddam Hussein's regime for slowing the flow of $105 million in U.S. aid by placing mines in the port of Umm Qasr. 

U.S. Navy helicopters flew two dolphins - Makai and Tacoma - into Umm Qasr, where they were to begin ferreting out mines Wednesday ahead of ships carrying relief supplies. 

A British ship, the Sir Galahad, moved into the Khor Abdallah river Tuesday night with 211 tons of food and 101 tons of bottled water. It was to head up to Umm Qasr on Wednesday. 

Iraqis have about five weeks of food left, according to estimates by the World Food Program. About 13 million people - 60 percent of Iraq's 22 million - are completely dependent on food handouts, 

The World Food Program, a U.N. agency, said it would make its biggest single request for cash in its history - more than $1 billion to help feed the war-stricken nation for about six months. 

"This could well turn into the largest humanitarian operation in history," said agency spokesman Trevor Rowe. 

Conditions in Basra, where British troops shelled Iraqi fighters on Tuesday, seemed especially severe. Annan called for "urgent measures" to avert a major crisis there. 

Electricity and water supplies have been cut off in Basra, and many of the million-plus residents are drinking contaminated water and face the threat of diarrhea and cholera. 

The U.N. Children's Fund estimated that up to 100,000 Basra children under age 5 were at immediate risk. 

On Wednesday, Al Jazeera television showed residents lining up to buy water at one of the city's few working wells. 

Before the war, Iraqis depended on government rations distributed under the U.N.'s oil-for-food program. The 7-year-old program allows Iraq to sell unlimited quantities of oil to buy food, medicine and other humanitarian goods. The proceeds from oil sales are deposited in a U.N.-controlled escrow account. 

The war has thrown the future of that program in doubt. 

Because the United States and Britain failed to get U.N. backing for the war, Russia, France, Germany and China want to ensure that the immediate humanitarian costs of the war are paid by the United States - and not the United Nations. 

Annan wants to revive the U.N. aid program as quickly as possible. A resolution giving him authority to run the program for 45 days is stalled because Russia, Syria and others are insisting the United Nations must not sanction the war or give the United States control over the U.N.-controlled account, which holds billions of dollars.