By Ryan Dilley BBC News Online correspondent in New York

The relatives of the thousands still missing in the rubble of the World Trade Center are now being offered certificates that confirm their loved ones as officially dead.

The USS Comfort towers over the squat buildings of Pier 94, on Manhattan's western shorefront.

The hospital ship, with its doctors, intensive care beds and operating rooms, was rushed to New York to help treat the flood of casualties expected to emerge from the devastation at the World Trade Center.

Its impressive facilities have remained for the most part unused.

Just as the continuing search and rescue effort at "ground zero" has shifted towards a more vigorous removal of debris, at Pier 94 attention has moved from the medics of the USS Comfort to the lawyers now setting up shop in the neighbouring Family Assistance Center.

The certificate gives me closure

Jill Olcott

Wednesday is the first day that the kin of those who have yet to be found in the twisted remains of the WTC are being allowed to apply for their loved ones' death certificates.

A steady stream of grieving families crosses the busy Westside Highway to the gates of the centre, many intent on taking up Mayor Rudolph Giuliani's offer to begin the paper work which will formally declare their missing husbands, wives, fathers, mothers, sons and daughters dead.

Tony Guzzato has lost his wife Barbara in the tragedy. "At this point there's really not much hope. You've got to be realistic," he says.

The process of gaining a death certificate for a person missing is a rare and time-consuming one, and even some of the lawyers donating their services at Pier 94 have had to be specially schooled in its finer details.

Financial burdens

But with so many breadwinners lost in the WTC terror attacks, city officials have streamlined the procedure to help ease the financial burdens of those left behind.

"I need to keep a roof over my head and feed the children," says Mr Guzzato, leaving Pier 94.

Salma Achmed, whose father Shabbir worked on the 107th floor of the twin towers, says her family cannot access his bank account without the certificate.

I don't feel better having filled in the forms. I still can't go back to work or go back to my life. I'm in limbo

Lynne Ruback

"Applying for it also makes me feel a little better. It concludes everything," she says.

Jill Olcott says she knows her father Gerald has died in the collapse.

"The certificate gives me closure. It was also helpful and comforting to come here see the other families and know I'm not alone."

Elizabeth Rivas has come, with her son Alex Barragan, for the certificate of her husband Moises - a chef at the Windows on the World restaurant.

"I didn't like to do it. I don't need the money, but I was pressured by my husband's side of the family. I had to get the certificate before them. It's right that it should go to his children."

Holding out hope

Defiant in 'Osama: Wanted dead or alive' T-shirt, Mr Barragan says that applying for the document does not mean he thinks his stepfather is dead.

"We still have hope. He's a missing person. Why give up hope? He was way up at the top of the building, so there's still a chance."

Lynne Ruback says that everyday the realisation that her firefighter husband Paul is not going to come home becomes more final.

Mr Ruback and several colleagues from FDNY Ladder 25 were thought to be assisting the evacuation of tower two when it collapsed.

Alex's father was a chef at the Windows on the World restaurant

"The littlest of our five children are still hopeful. They think he might still be found," she says.

Mrs Ruback says she was told of Mayor Giuliani's offer by a friend: "I've stopped watching TV now."

She thought it was mandatory to apply for the certificate, and did not realise the process is still just an option for those grieving.

"I don't feel better having filled in the forms. I still can't go back to work or go back to my life. I'm in limbo. At best it gave me something to do, something to keep me moving," she says.

Mrs Ruback says she was looking forward to her husband retiring from the fire department next January.

"I had to get a death certificate for my mother last year, but I never dreamed I'd have to be doing it for Paul."