A senior U.S. official confirmed to FOX News that the severed fingers of five Western hostages were delivered to U.S. government officials in Iraq, giving the men's relatives hope that they are still alive.

The Austrian weekly magazine News first reported the delivery of the five fingers in Wednesday's edition, citing unidentified authorities working on the case.

One of the kidnap victims in Iraq was a University of Florida student. The hostages have been missing for more than a year and U.S. authorities in Baghdad recently were sent their severed fingers.

Four of the men had been working as contractors when they were captured in a brazen ambush of their 43-truck supply convoy on Nov. 16, 2006.

The men were working for Crescent Security Group, a Kuwait-based private security company. They were kidnapped by men in Iraqi police uniforms who ambushed the convoy they were escorting near the southern city of Safwan.

Patrick Reuben, a Minneapolis police officer whose twin brother, Paul Reuben, is among the missing, said late Wednesday the FBI told his family that "the fingers were confirmed to be those of the hostages."

Patrick Reuben told The Associated Press the news of the severed fingers was "shocking" but that the initial word the family got was "much more serious than that. Later on we found that it was fingers that were recovered and that the DNA confirmed it was the hostages."

FBI spokesman Richard Kolko said the agency continues to investigate the whereabouts of the five men missing since 2006, as well as a sixth man, Ronald Withrow, an American who was kidnapped separately from the others and whose finger apparently was among those sent to officials.

"The investigation continues into the whereabouts and safety of the five men kidnapped in Iraq," Kolko said. "The FBI has received DNA evidence and is conducting an examination. Additionally, the FBI's Office of Victim Assistance has been working with the U.S. families involved in this matter."

Kolko continued: "They have been kept up to date on information the FBI had available and were notified of the DNA samples in February. We understand this is a very difficult time for the families and discussing this matter further in the media is not appropriate."

The men were abducted in two separate incidents that occurred a month and a half apart more than two years ago, a U.S. government official said Thursday in Washington.

The six missing are Reuben, a former St. Louis Park, Minn., police officer; Joshua Munns of Redding, Calif.; John Young of Kansas City, whose finger was not among those sent to officials; Jonathon Cote of the Buffalo, N.Y., area; Bert Nussbaumer of Austria; and Withrow, 40, of Lubbock, Texas, a contractor working for JPI Worldwide who was abducted on Jan. 5, 2007, near Basra.

Reuben said his family is "certainly hopeful, but there's nothing definite right now."

State Department spokesman Sean McCormack declined Thursday to comment on the matter except to say: "We continue to demand these hostages' immediate release so that they can be returned safely to their families."

Proof of Life?

Cote's father said the FBI visited his and other families two to three weeks ago, when they were told DNA samples had been identified as those of the hostages. The agents would not say how they had gotten the samples.

When Francis Cote read a news report about the fingers, he contacted the State Department but was given no confirmation or denial.

"They told us the FBI would visit us," Cote said.

Cote received calls Wednesday from Paul Reuben's wife, who was in tears, and Munns' mother, as well as Crescent Security. The hostages' families frequently contact each other to share news and compare notes, he said. Cote assured the women the hostages are alive.

"It's possible they did sever [the fingers] to show proof of life," Cote said. "I'm sure somebody from our government was asking for proof of life and I guess proof of life was severing a finger versus delivering a video."

Cote said he was frustrated by the government's reticence.

"We have no news; we have activity," has been the extent of officials' comments on the hostages for months, Cote said. "It's very vague."

''I'm thinking that he's still alive and obviously missing a finger, but doing well,'' Cote said on Wednesday night from his home near Buffalo, N.Y. "We pray to God that he takes care of him, and he's brought home as soon as the plan allows.''

After graduating from high school in New York, Jonathon Cote joined the U.S. Army, where he served four years. He was in Afghanistan and Fallujah, Iraq, his father said, and while there, he realized there were lucrative job opportunities in the private security sector.

He tried unsuccessfully to get a job and decided to go to college instead, choosing the University of Florida.

''He wanted to be in the sunny weather,'' Francis Cote said. "He had been tired of living in the desert with the Army. He wanted to live life a little bit.''

His mother, Lori Silveri, also lives in Florida.

He spent a year at Florida, starting a major in accounting and moving to a course of study in physical training.

But Cote wanted to get back in the line of fire — and he wanted to make some money. He took a job with the Kuwait-based Crescent Security and was in a convoy near the southern Iraqi town of Safwan, near the Kuwaiti border, when he and four others were kidnapped.

While in college he joined the Sigma Phi Epsilon fraternity and made close friends.

''Jon was always the life of the party — people loved him,'' said David Hankins, one of his pledge brothers. "When we were pledging, we got all the crap, but he got along really well with the older brothers.''

UF spokesman Steve Orlando said the school's thoughts were with Cote's family after Wednesday's news.

''Obviously we're thinking about his safety and what his family is going through right now,'' Orlando said. "We know it's a difficult time for them right now, and we're hopeful that things will turn out for the best.''

The Crescent contractors appeared in two hostage videos released in December 2006 and January 2007, in which they pleaded for the United States to withdraw troops from Iraq and free all Iraqi prisoners. In the videos, they appear in good condition and say they are being treated well.

No financial demand has been made public, and it is unclear what group is holding the men. All the hostages were seized in southern Iraq, where powerful Shiite Muslim militias operate with relative freedom.

There was no word on a fifth contractor, John Young of Kansas City, who was seized with them. None of the fingers belonged to him, authorities said.

''The government is in touch with us, but they said nothing has been verified yet,'' said Sharon DeBrabander, Young's mother. "I certainly don't understand why my son wasn't found. What does that mean?''

Munns' mother, Jackie Stewart, learned from a reporter that her son's finger had been cut off, and the FBI confirmed it to her later that day, she said.

"The fact that my son lost a finger is very disturbing," said Stewart, the mother of Joshua Munns. "But if they haven't killed him now, I seriously doubt they will, unless something tragic happens, something devastating."

Stewart said the FBI asked her for a DNA sample about a month ago, saying they had some evidence to test it against.

"A couple weeks later they called me back and said yes, we did have a match," said Jackie Stewart of Ridgefield, Wash.

The FBI did not tell her at the time where her son's DNA came from, she said.

Withrow, a computer specialist who worked for JPI Worldwide, was kidnapped separately at a phony checkpoint near the southern Iraqi city of Basra on Jan. 5, 2007.

Very little information is publicly available about his abduction; the bodies of his Iraqi translator and driver were discovered the next day.

His employer is a Las Vegas-based company that provides Internet and technological support to remote or war-torn areas around the globe, according to the company's Web site.

Austrian officials said at a news conference in Vienna that U.S. officials had provided information about ''fingerprints and DNA traces that were positively matched to Nussbaumer,'' the Austrian hostage. They did not confirm that the sample was a severed finger.

Police. Col. Rudolf Gollia, a spokesman for the Austrian Interior Ministry, said the report that the severed fingers had been sent to U.S. authorities was being treated as a rumor.

He said U.S. officials in Baghdad forwarded information to the Austrian Embassy in Amman, Jordan, that the Americans were described only as "based on fingerprints and DNA profiles."

He said Austrian officials were trying to get more information from U.S. officials and other sources in the Middle East.

"I'm happy that that there is sign of life from Bert after all this time," Franz, his brother, said Thursday about reports that Austrian authorities are in possession of a fingerprint from Bert that might have come from a severed finger.

"It might sound strange," said the 25-year-old by phone from the Upper Austrian village of Neukirchen. "But it's a positive sign in any case — whether we're talking about finger prints or a finger."

Anna Feichtinger, the brothers' grandmother, is clearly worn after 14 months of anxiety.

"I don't know what I should think," she said. "I can only pray — every day."

And Franz Nussbaumer said the report that Bert, 26, had been mutilated "initially shocked our mother" Maria Nussbaumer.

"Still it is at least concrete news," he said. "The worst has always been the lack of knowing what is going on with him.

"We believe that he is alive and continue to do so until the opposite is proven."

Maria Nussbaumer, the mother, also clings to hope.

"Bert lives," she said. "And I know that one day he will appear in front of my door."

FOX News' Jennifer Griffin and The Associated Press contributed to this report.