Seen just after sunset, rushing through in a US Marine convoy that would not stop, it was pocked by unnatural fires, flickering in the heart of scorched trucks and tanks. In the near-darkness it was just possible to make out the ugliness of the quick, nasty battle waged in this small town in order to push the Marine Corps through it, to the threshold of Baghdad.

A scorched row of shops. A truck, still burning in front of a restaurant. Figures silhouetted against the leaping flames on the roof of a building as they jumped hither and thither to try to put the fire out.

The town was unlit, but civilian traffic with headlights on moved through the streets. A civilian ambulance, red lights flashing, was trying to negotiate its way through a US Marine checkpoint on the main road which skirts Aziziya.

Beyond the town, on a hot, still night loud with frog song, more fires could be seen reflected in pools in the date groves. An Iraqi tank transporter, complete with tank, was on fire where it had slewed into a ditch after being hit.

The resumption of the blitzkrieg which has now taken these Marines to within 40 miles of the Iraqi capital shows the ruthless logic of the tactics on both sides.

US forces wanted to get past Aziziya safely, without actually taking it. That meant hostile forces in the town had to be neutralized. Iraqi forces mingled their troops and equipment with the civilian population. Inevitably, civilians got caught in the crossfire; and the US is not yet helping them with drugs or hospital treatment or repairs or law and order, because the US is not entering the city, leaving whatever dubious conjunction of desperate Baath Party hacks, looters and elders remains to organize relief.

From the conflicting information given by local people in interviews with the Guardian, it seems that the town was subject to preliminary attack by planes, helicopters and artillery. The Marines sent tanks through Thursday morning, followed by battalions of infantry whose aim was simply to get past the town and head on toward Baghdad without getting hurt. If they were fired on, they fired back, even if it meant firing into nominally civilian areas.

One local man, who seemed to speak with genuine anger, said 50 civilians had been killed in the fighting, including women and children, and 50 wounded. He said all the dead had been buried but could not say exactly where.

“They sent bombs like silver rain,” said the man, Abdel Karim. In the background, a huge oil storage tank gushed flames and black smoke. “These are innocent people. They are not fighting.”

Another resident, who would not give his name, said — once the mob of dozens had drifted away — that Karim was speaking to curry favor with the Iraqi authorities, and most of the dead and wounded were members of the Republican Guard or local Baath Party fighters.

Asked why he would not give his name, he said: “I am afraid nothing will happen to my friend, and we will be slaughtered.” By “my friend” he meant Saddam Hussein. “We are not angry with the Americans. For 35 years the Baathists have been killing us, suffocating us. Even if the Americans killed me the sacrifice would be worth it.

“The army and Baath people go into hospitals and schools and put themselves in the middle of the civilians. Over 100 of the Republican Guard and Baath were killed last night. The ones they buried are military but they wear the dishdash (civilian tunic).”

Another man spoke of the agony of being between two opposing forces. “Don’t bomb us any more, we have children,” he said. “We are afraid he will use chemical weapons, and we don’t have masks.” “He” was another euphemism for the president.

A woman dressed in the traditional abayah, with Bedouin tattoos on her face, was driving with her sons out of Aziziya. She clutched a pair of her husband’s white boxer shorts as a white flag.

She said she had seen the bodies of dead civilians, including women and children, who had been killed as they fled the city. The Americans had used cluster bombs, she said. Two of her sheep had been wounded. “They also have souls,” she said.

The Marines crossed their pontoon bridge over the Tigris overnight and in the course of the day raced past Aziziya and toward Baghdad along Highway 7. It was like some insane race: a column of Humvees charging down the wrong side of the dual carriage way, half on, half off, overtaking and being overtaken by tracked amphibious vehicles going in the same direction.

On the far side of the road, tanks, also heading north at 40 mph. In a tracked vehicle, that is fast. Brick-sized chunks of rubber from the vehicles’ tracks flew into the air and bounced off the tarmac, and the noise of diesels and gas turbines going at full power was deafening. The US Marines had Baghdad fever. In a single day, the Marines of the 5th Regiment advanced some 30 miles closer to the capital. By day’s end the regiment’s furthest forward unit was only 30 miles from the city.

No one was saying openly that they were competing with their service rivals, the US Army, to be first to reach Baghdad. But one senior officer said of the commander of the 1st Marine Division, Gen. John Mattis: “The general said the leash is off.”

Thousands of civilian Iraqis, in cars, pick-up trucks, coaches and trucks, were mixed up in the Marines’ drive forward. They were heading in both directions along Highway 7 between Kut and Baghdad. They waved, smiled, and shouted fragments of English like: “Thank you!” and “Good, good!” It was hard to tell whether their apparent happiness was genuine or expedient or a mixture of both.

People who have lived under a totalitarian regime for decades learn how to tell those in power what they think they want to hear, and if Marines like smiles and waves, it costs nothing to give them.

Yet many of the greetings, particularly from the young and the old, seemed genuinely warm, tinged with the excitement of novelty. For some of the young men, the well-fed ones with short haircuts, it may have been partly relief that they were still alive. Near where an Iraqi T-55 was burning on the approach to Aziziya, the road was littered with discarded Iraqi uniforms.

From fragments of conversation with a crowd all speaking at once, it seemed many of the Iraqis had homes in Baghdad, had set out early to reconnoiter in preparation to evacuate their families southward, and then run into the Marines on the way back. Now they were cut off.

Asked about the fighting, one man, Abbas Hussein, said: “They all ran away. It is finished.”

It was not clear on Thursday night the extent to which the Marines had bloodied their main conventional opponent on the way to Baghdad, the Nida division of the Republican Guard.

At around noon yesterday, Lt. Col. Sam Strotman, a senior Marine officer, stood on a rise overlooking the smoke from Aziziya. “You can see what happened to the lead trace of the Nida division when they met 2nd Tank (Battalion of the Marines),” he said.

“There are two groups of people: the people being forced to fight and the people who really wanted to fight, and I think the second number is extremely small.

“I think there’s also a cultural issue of time and space. They can’t believe we got here this fast and in such numbers. None of our systems are designed to do anything like this and when I think of what these young Marines have done it’s amazing.”

He said the Republican Guards were caught in a dilemma; they could stay in place and be attacked by Marine ground forces, or they could move and be destroyed by Marine air forces.

Could unconventional weapons still save President Saddam? Twice on Thursday, with temperatures rising to 35C (95F) in the shade, the Marines heard the call of “Gas! Gas! Gas!”

Both times it was a false alarm but for half an hour the troops sweltered in their tight-fitting rubber masks and thick NBC suits.