The toll of those missing from the attack on the World Trade Center has now risen above 6,300.
"We now are at least 6,333 reported missing," New York's Mayor Mr Rudolph Giuliani said.
No one has been found alive in wreckage of the towers since the day after the attacks, and New York city officials have admitted there is now very little hope for those still missing. Officials have so far confirmed 241 people were killed.
A spokeswoman for the Department of Foreign Affairs told ireland.comthis afternoon the total figure of Irish people who perished in last week's attacks in the US had not been finalised.
"It is very difficult to be sure at the moment. It may take some time, but the total may well be in double figures."
Five Irish people have been officially confirmed dead in the attacks.
She also repeated calls for family and friends of missing people who are in the US illegally to contact them.
"People shouldn’t be deterred from contacting us if their relatives were working illegally," she said. "Our sole concern is for their safety at this stage."
Meanwhile the Department has issued a warning to all Irish citizens against travelling to Afghanistan in the light of the US military build-up in the area.
A statement from the Department also advised travellers to cancel all non-essential visits to Pakistan, where anti-Western demonstrations are escalating.
"Those travelling abroad should exercise extreme caution and vigilance and pay close attention to advice from security authorities," the statement said.
