Updated

U.S.-led forces on Wednesday pounded President Saddam Hussein's desert hometown, where they said desperate loyalists were making a last stand as resistance in Baghdad crumbled.

U.S. Central Command said coalition aircraft were conducting strikes against military targets in Tikrit, "shaping the battlefield" before American ground forces move into the city, 100 miles north of Baghdad.

Aircraft were targeting the Republican Guard's Adnan division in Tikrit, U.S. military officials said. In nighttime raids this week, Navy warplanes have bombed a Republican Guard barracks and garrison there, said Rear Adm. Barry Costello, commander of the USS Constellation.

Lt. Mark Kitchens, a Central Command spokesman, said special operations forces were "actively engaging" Iraqi forces in the city.

"We certainly are focused on Tikrit," said Brig. Gen. Vincent Brooks, at a Central Command briefing in Qatar, "to prevent the regime from being able to use it as a place to command and control, to restore command and control, or to hide."

American troops have tried to block the roads into the city from Baghdad to stop Iraqi leaders from fleeing there.

Iraqi reinforcements already have moved to bolster the city's defenses, with some coming up from the south as allied troops moved into Baghdad, and others heading down from the north, ahead of advancing coalition and Kurdish forces, Brooks said.

The Iraqi fighters were likely a combination of military, irregular forces and Baath Party loyalists, he said. Brooks would not say when he thought coalition ground forces would move in, saying only, "There is still work to be done."

Asked if the 4th Infantry Division, which is preparing to deploy from Kuwait, might be sent to Tikrit, Capt. Frank Thorp, another Central Command spokesman, said: "I don't think it would be unreasonable, but I don't think we're going to say yet where actually they're going to be used."

An American F-15E fighter jet crashed near Tikrit on Monday. Central Command said it was investigating the cause of the crash and rescue crews were searching Wednesday for the crew.

Saddam, if he is still alive, may try to flee to his birthplace in the hope that tribesmen with blood ties to him will fight to the death for their leader. Even if he is dead, experts fear Tikrit would remain a hotbed of resistance long after a new government is installed.

The town owes a lot to Saddam. Before his Baath Party came to power in 1968, it was a backwater. Thanks to government investment in infrastructure and business — largesse straight from the man at the top — Tikrit has grown into a sprawling town of 260,000 people.

Along with the garrison for the Republican Guard, Iraq's best-trained troops, Tikrit hosts an air base and air force academy.

Saddam has also studded the town with some of his largest and most elaborate presidential compounds. If he went into hiding there, regime watchers say he could easily vanish into the labyrinth of underground tunnels believed to link those sites to the eastern banks of the Tigris River.

But the Patriotic Union of Kurdistan, one of two main Iraqi Kurdish groups opposing Saddam, claimed on Tuesday that Saddam already was hiding in Tikrit. The party's newspaper said Saddam, his two sons and many of his top aides moved there after fighting intensified in Baghdad.

How much resistance Tikrit could muster is not clear.

Tikrit is a power center for Sunni Arab tribes that may hold out for as long as possible out of fear of losing power to the nation's Shiite majority.

And if Saddam goes into hiding, he may be able to organize clandestine cells and launch a guerrilla war against U.S. troops similar to the one his Baath party waged in the 1950s.

"It is entirely possible that some residual elements of the Baath Party will reconstitute themselves as an underground revolutionary armed-struggle party that will launch terrorist attacks against U.S. forces and the interim authority," said John Pike, a military analyst at GlobalSecurity.org.

"Pacifying Tikrit is going to be a particular problem," he said.

In the Baath Party's early days, Saddam rose to prominence in 1959 by participating in a failed assassination attempt on then-Prime Minister Gen. Abdel-Karim Kassem.

Even back then, Tikrit served him well. After the botched assassination attempt, the young Saddam fled his hometown on horseback across the desert for neighboring Syria.