Iraqi officials said they expect Baghdad to be encircled in five to 10 days and predicted the campaign to unseat President Saddam Hussein will founder there.

Lead elements of the U.S. 1st Marine Division and the Army's 3rd Infantry Division are pointed at Baghdad's southern flank, where the Medina Division of the Iraqi Republican Guard is arrayed, as the two sides steel for what is likely to be the major battle of this conflict.

With the invasion of Iraq entering its second week and Saddam apparently still in power, President Bush said that the war will continue for "however long it takes."

"This isn't a matter of timetable — it's a matter of victory," the president said. "And the Iraqi people have got to know that. They have got to know that they will be liberated and Saddam Hussein will be removed, no matter how long it takes."

After eight days of fighting, Pentagon officials said close to 90,000 U.S. troops were in Iraq, and that an additional 100,000 to 120,000 were on the way. All were part of a military blueprint made up long ago, officials said, sensitive to criticism that commanders had underestimated the need for troops to quell stronger-than-expected resistance or protect long supply lines.

When all the U.S. troops arrive, more than half of the U.S. Army and Marine Corps will be in Iraq.

The bombing of Baghdad picked up overnight as a U.S. B-2 bomber dropped two 4,700-pound, satellite-guided "bunker busting" bombs on a major communications tower on the east bank of the Tigris River, U.S. military officials said. They said the strike was meant to hamper communications between Saddam's regime and Iraq's military. Air assaults zeroed in on one of Saddam's presidential compounds in the heart of the capital.

"Coalition air forces and Tomahawk missiles took out communications and command and control facilities in the capital city during the night," said Lt. Cmdr. Charles Owens, a spokesman reading from a bulletin at the command center in Camp As Sayliyah.

There was some movement forward yesterday. A northern front began to take shape as U.S. paratroopers moved into position in Kurdish-controlled territory and the first Iraqi lines collapsed.

And U.S.-led forces in central Iraq pounded Iraqi positions in and around the city of An Najaf. They also fought near the southern city of Nasiriyah for a fifth day and along key supply routes that form the spine of the allied advance on Baghdad.

But throughout the combat theater, military commanders scrambled to readjust their battlefield plan. U.S. and British forces continued to encounter unexpectedly stiff resistance in parts of southern Iraq.

While the weather had been blamed for delays in the charge toward Baghdad, some of those on the front lines acknowledged that the 2nd Brigade of the 3rd Infantry Division may have advanced too rapidly and needed to hold up.

Military planners said they had anticipated none of the resistance in cities such as Nasiriyah and An Najaf. They had intended to bypass population centers, concentrate on severing the central government, and then await surrenders from smaller commands.

"I honestly think they had us move so fast because they thought it'd be a fast collapse," said Capt. Steven Barry, commander of "Cyclone" Company in the Army's 4th Battalion, 64th Armored Regiment. "Now that they realize it's not going to be a fast collapse, they've decided to slow down and be more deliberate."

Supply-line problems added to the rigors facing forward units of U.S. troops, now within 50 miles of Baghdad. Attacks on U.S.-British convoys and three days of sandstorms and foggy weather had slowed the delivery of badly needed supplies of food, water, ammunition and spare vehicle parts.

In at least one Marine unit, MREs, "meals ready to eat," were being rationed at one a day because of short supplies. Some damaged helicopters were kept grounded by a lack of spare parts.

U.S. commanders predicted that improved weather today would speed the convoys and allow for the more efficient stockpiling of supplies where the forward troops could use them.

One such forward base opened for business yesterday after being captured by U.S. forces Saturday. A C-130 supply plane landed at an airfield in Tallil, just outside Nasiriyah, bringing the first of many planned shipments of materiel and troops. Wags posted a sign reading: "Bush International Airport."

Improved weather is also expected to allow light infantry forces to move north. Some units were slowed or halted yesterday by foggy weather, although others reveled in sunshine after two days of sandstorms that had turned the sky a soupy orange.

U.S. officers stressed that their forces had moved at impressive speed until bad weather and stiff Iraqi resistance slowed the advance north.

"We went 200 miles in two days," one officer said. He noted that Gen. George S. Patton's 3rd Army moved 100 miles in two days to relieve U.S. forces at Bastogne in 1944.

Coalition planes flew 500 bombing runs yesterday, striking 200 targets, Air Force officials reported. For the second day in a row, the top-priority targets were the Medina Division, south of Baghdad, and the Hammurabi Division in the north.

Iraq's defense minister, Sultan Hashim Ahmad Jabburi Tai, predicted that the war will come down to a decisive street battle in Baghdad. Iraq will win, he insisted, although the war might last for months.

"They have to come into the city eventually," he said. "The enemy can bypass the resistance and go in the desert as far as it wants. In the end, where can he go? He has to enter the city."

In Baghdad, Iraqi TV also showed more footage of Saddam; it could not be determined when the black-and-white pictures were taped.

Jabburi Tai, the defense minister, said a total of 350 Iraqi civilians had been killed. The independent Doctors Without Borders confirmed at least 250 wounded in Baghdad alone, including many women, children and elderly.

A spokesman for the U.S. Central Command in Doha, Qatar, suggested yesterday that a missile attack on a Baghdad market Wednesday that killed more than a dozen people may have been a case of the Iraqis bombing themselves. Brig. Gen. Vince Brooks said the Iraqis are using old, defective stocks and are firing without activating radar systems that would improve aim but enhance the risk of detection.