WASHINGTON - About a dozen US troops have been killed so far in the offensive against the Iraqi city of Fallujah, US Lieutenant General Thomas Metz said Tuesday, without giving a precise toll.
"You can count our casualties in certainly a dozen," Metz said.
"I would not want to characterize it beyond that. It is light," he said in a videoconference from Iraq.
Earlier, gunfire and mortar rounds sounded through the streets as US marines moved deep into Fallujah meeting resistance from snipers hidden in damaged buildings and mosques.
Black and white smoke plumed skyward as US artillery, war planes and tanks pounded the Sunni Muslim bastion west of Baghdad, meeting minimal opposition as the insurgents withdrew, an AFP correspondent embedded with the military said.
"Right now they are observing us as we get closer, they are fading back to secondary positions and adapting to our tactics," said Lieutenant Colin Browning, as his troops advanced cautiously through the northwest Jolan neighbourhood, the main centre of resistance here.
"As we get further in it's going to get worse," he said.
The battle to reclaim the insurgent enclave, so-called "Operation Dawn" launched by Iraqi Prime Minister Iyad Allawi late Monday, spread through neighbourhoods and alleyways from the north towards the centre.
US commanders estimate that 2,000 to 2,500 fighters, some loyal to Iraq's most wanted man Abu Musab al-Zarqawi, are inside the city and its surrounding areas, ready to fight.
An AFP correspondent in Jolan said the area had been flattened and was a wasteland of glass and rubble, a desolate scene with no civilians or bodies in sight, more a ghost town than an insurgent bastion.
Unconfirmed estimates suggest that as many as 100,000 residents could still be in the "city of mosques" but many of the houses appeared to have been deserted long ago, containing neither furniture nor other possessions.
The only signs of life are chickens and roosters darting crazily around the dusty streets amid a constant crackle of AK-47 assault rifle fire and the thud of mortar rounds. Heavy artillery shells littered the streets.
The sniping is a deadly game of cat and mouse. Browning jumped down from one roof top overlooking a mosque a few hundred metres (yards) away.
"There are two guys with AKs hiding in this minaret," he said. The top of the mosque, one of many, was nicked and battered by gunfire.
As they go, the marines carry 35-40 pounds (around 16 kilograms) of gear on their backs including 15 magazines of 28 rounds, grenade launchers and their own weapons, and literally kick the bricks out of walls they can't get around.
"It's a good day, no one's been hurt so far, knock on wood," said Lance Corporal George Payton, lathered in sweat and grease stains.
An AFP reporter saw a man firing a rocket launcher from behind a mound of earth. Tanks arrived and rained heavy machine gun fire on the position.
While the reporter could not verify if the man was dead, all firing from his position stopped.
US marine spokesman Lieutenant Lyle Gilbert said earlier: "As for casualties on the insurgents' side I can tell you that they are dying. A lot of them are dying and this is a good thing."
After taking key positions on the western edge of the city early on Monday, thousands of US troops, followed by crack Iraqi soldiers launched a two-pronged assault Tuesday into Jolan and the Askari district in the northeast.
The troops "faced resistance at the beginning but there is almost no resistance now," another high-ranking US officer said.
"They are less than one kilometre (half a mile) from the centre," he added.
Thousands of Fallujah's 300,000 residents have fled to surrounding camps or to Baghdad, where a curfew was imposed Tuesday, as living conditions deteriorated and fears grew of the impending assault.
Doctors inside the besieged city have painted a grim picture amid a chronic lack of medical equipment, trained staff, water and electricity.
Despite its superior manpower, the US military is anxious to put an Iraqi face on the Fallujah assault for political reasons, and a smattering of specially trained Iraqi forces accompanied the marines.
Others were poised on the outskirts of the city, preparing to enter.
Already battered for weeks by US aircraft and artillery, Fallujah bled smoke from the north and west after a punishing 24 hours of even more relentless bombardment.
Attack helicopters swooped overhead, dropping flares on buildings from where the muzzle of insurgent rocket heads jutted out, while militants lashed back with anti-aircraft fire, the AFP reporter said.
"Nothing is being indiscriminately fired at. These are spots where they (militants) are either getting ready to fight or already are," said Major Todd Desgrosseilliers, an executive officer with the marines.