FALLUJAH, Iraq – Terrorists in Fallujah are highly organized and using classic tactics to mount a fierce struggle against the overwhelming might of the American military, American commanders have acknowledged.

Although American forces now theoretically control nearly three-quarters of the city and claim to have killed 600 fighters in the Sunni bastion, an overall victory leading to the long-term pacification of the city is not assured.

With only minimal night-vision equipment, the terrorists are choosing to fight mostly in the day. Messages are often passed by bicycle courier because mobile phones are subject to jamming or electronic monitoring and cars will be bombed.

They are using their knowledge of local geography to draw troops in and fight briefly, only to retreat before precision munitions can be used.

“There are holes in the backs of buildings they’re fighting in and they’ll rabbit-jump from building to building as we prosecute engagements,” said Captain Raymond Pemberton, an intelligence officer for the American Army’s Task Force 2-2.

Soldiers from 2-2’s Scouts platoon miraculously lived to tell the tale of these tactics after a fierce firefight on Wednesday evening. Sergeant Jason Laser was entering a room in a complex of 20 buildings when he came face to face with a gunman.

“Through my night-vision goggles I could see he had a black beard and some kind of headdress. He opened fire with an AK-47, hitting me in the chest and knocking me completely over. The first three of us into the building were hit.”

Sergeant Laser’s body armor saved his life, leaving only a bruise and an impression of his dog tags on his chest. A second bullet hit his M-16 rifle and sliced into his index finger. A third grazed his neck, while a fourth lodged in his neck protector.

The other two soldiers were also superficially wounded, and the troops were forced back. At least eight insurgents melted into the night before a JDAM bomb destroyed that part of the complex.

Earlier, another insurgent had shown remarkable military skills and presence of mind. “We fired Bradley [25 mm] rounds, tank rounds, incendiary grenades, and everything at him and he still kept going,” said Sergeant Laser.

The fighter “cooked off” a grenade pulled the pin and waited several seconds before coolly dropping it down a stairwell, causing the Scouts to dive for cover. When an armored bulldozer was brought in to level the building, he shot at it before disappearing.

There is a danger that Fallujah could see a repeat of last year’s Iraq invasion, in which the overall objective was secured in record time but a fierce resistance sprang up afterward.

But there is little sign of complacency among senior officers, who give the terrorists credit for mounting a stiff defense.

“They’re like military organizations,” said Major John Reynolds, 2-2’s operations officer. “They have platoons and they report to a company. They had observers, they put out IED’s [improvised explosive devices], they had a citywide plan to move back.”

Although the American battle plan has unfolded as predicted, so too, perhaps, has that of the insurgents, who seem to be heading for a point in the west of the city.

“Nothing has changed over the past 200 years in terms of guerrilla tactics,” said Captain Pemberton. “They are coordinating their movements and setting up ambushes. Tactically it’s a sound operation. They’re not fighting a fixed fight.”

Bombs and mines were planted to disrupt the American advance, while professional fortified positions and dugouts were created in the east in preparation for a breach from that direction.

In fact, the breach came from the north, but the terrorists had planned for all eventualities.

The American commander, Major General Richard Natonski, said 18 American servicemen and five Iraqi government soldiers have been killed in action since the start of the assault. He said 69 American and 34 Iraqi fighters had been wounded. The Marines have had significant casualties.

Lieutenant Colonel Pete Mewell, 2-2’s commander, said it was possible that some fighters had fled before the battle began. “The ones that were here when we started have no chance of getting out…If they’d stand and fight it’d be a lot easier,” he added.

As he spoke, there was a deafening boom of American Paladin artillery guns.

“That would be the last sound they ever heard.”