Italian news reports said the victims were a Nigerian woman in her 30s and the driver of one of the two trains.

Officials said one train was stopped in the station when it was hit from behind by another travelling at a high speed.

Some passengers said the driver of the second train appeared to have jumped a red light.

About 60 people were injured, including 10 seriously, said another Rome fire department spokesman, Luca Cari.

Television footage showed stunned and bloodied passengers being led out of the station, while onlookers watched from behind police lines.

Ambulances, firefighters and rescue teams rushed to the Piazza Vittorio Emanuele II subway station, near Rome's main railway station, after the crash soon after 9am local time. Rescue workers set up a field hospital nearby.

Firefighters had to free at least one more person trapped in the wreckage, Cari said.

"For now, we don't know about any more people trapped, but we can't rule it out," Cari said.

She received third-degree burns to an arm in the fire Sunday night at her home in the town of Rhine south of Elkhart Lake, the Sheboygan County Sheriff's Department said, adding that both pets died in the fire.

Hanson, who lost a leg in a car accident three years ago, said she was on the couch watching television when the cat ran over the back of the couch.

"And he jumped onto a table that had a candle on it and tipped it over and lighted the artificial plants on fire," she said.

Hanson said she fell off the couch and was unable to get her artificial leg from the table, "so my dog got my leg for me and went and got the phone and brought the phone to me so I could call 911."

She said she tried to put the prosthetic leg on, but it was too hot, and the dog, a golden retriever-German shepherd mix, came to her aid again before going back inside for the cat.

When rescuers arrived, the house was fully engulfed in flames, the sheriff's department said. Hanson was in the doorway and was assisted by a deputy.

She was no longer being treated at the hospital when The Associated Press called Monday evening for further comment.

The vessels were the 712-foot Greek freighter Zagora, which was heading down river at the Kenner Bend area west of New Orleans, and the 737-foot Panamanian freighter Torm Anholt, which was at anchor at the time of the collision.

The Torm Anholt had a 12-foot-wide, 6-foot-long gash in its right side 6 to 9 feet above the water line. The ship listed after being struck, but the tilt may have been due to a loss of ballast, the Coast Guard said.

There were no reports of damage to the Zagora.

The Coast Guard established a one-way traffic safety zone in the area, but river traffic was not halted, Bandrowsky said.

"I don't think anybody believes it will be the precise moment when the population hits 300 million," Howard Hogan, the Census Bureau's associate director for demographic programs, said in an interview before the milestone was reached. But, he added, "We're confident that we're somewhat close."

It's not easy estimating the exact number of people in a country the size of the United States. It gets even more complicated when you take into account illegal immigration, another reason for the federal government to let the milestone pass quietly.

When the U.S. population officially hit 200 million in 1967, President Johnson held a news conference at the Commerce Department to hail America's past and to talk about the challenges ahead. Life magazine dispatched a cadre of photographers to find a baby born at the exact moment, anointing a boy born in Atlanta as the 200 millionth American.

This year, there's a good chance the 300 millionth American has already walked across the border from Mexico.

"It's a couple of weeks before an election when illegal immigration is a high-profile issue and they don't want to make a big deal out of it," said William Frey, a demographer at the Brookings Institution, a Washington think tank.

Commerce Secretary Carlos Gutierrez said the Bush administration isn't playing down the milestone, though he said he had no plans for Tuesday. Census Bureau employees planned to mark the moment Tuesday afternoon with cake and punch.

"I would hate to think that we are going to be low key about this," said Gutierrez, whose department oversees the Census Bureau. "I would hope that we make a big deal about it."

Gutierrez said America's growing population is good for the economy. He noted that Japan and some European countries expect to lose population in the next few decades, raising concerns that there won't be enough young people entering the work force to support aging populations.

"This is one more area where we seem to have an advantage," Gutierrez said. "We should all feel good about reaching this milestone."

The U.S. adds about 2.8 million people a year, for a growth rate of less than 1 percent. About 40 percent of the growth comes from immigration. The rest comes from births outnumbering deaths.

The Census Bureau counts the population every 10 years. In between, it uses administrative records and surveys to estimate monthly averages for births, deaths and net immigration. The bureau has a "population clock" that estimates a birth every seven seconds, a death every 13 seconds and a new immigrant every 31 seconds. Add it together and you get one new American every 11 seconds.

The 300 millionth American - born months ago or on Tuesday - is probably Hispanic because they are the fastest growing demographic group in the U.S., Frey said.

Jeffrey Passel, a senior demographer at the Pew Hispanic Center, said the Census Bureau has improved its population estimates in the past few years, but it still undercounts illegal immigrants.

There are an estimated 11 million to 12 million illegal immigrants in the U.S. Experts differ on the specifics, but many estimate that more than 1 million of them don't show up in census figures.

"The census clearly misses people," said Passel, a former Census Bureau employee who used to help estimate the undercount. "Having said that, when they crossed 200 million, they were missing about 5 million people. We think the 2000 census missed a lot less than 5 million people."