The remains of two more people who died during the 9/11 attacks in 2001 have been identified as part of a decades-long effort to return them to their families.
A man and a woman were both identified, New York City officials said, but their names have been withheld.
The city’s medical examiner has now identified 1,649 World Trade Centre victims through their remains, using DNA sequencing to test fragments from the bodies discovered in the rubble.
Advancements in technology, which include increased test sensitivity and faster turnaround times, mean remains that have tested negative for identifiable DNA can now be identified.
The same methods are used to identify missing service members in the US military, as well as to test the remains of more than 100 people who died during the wildfires in Maui last month.
However, despite the advancements in the technology the rate of positive identifications has slowed in recent years, with the last being two years ago, and then again two years before that.
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There are more than 1,000 human remains from the attacks that are yet to be identified, and are currently being stored at the National September 11 Memorial & Museum at the World Trade Centre site.
Dr Jason Graham, the city’s chief medical examiner, said officials were committed to fulfilling their “solemn pledge” to return the remains.
“Faced with the largest and most complex forensic investigation in the history of our country, we stand undaunted in our mission to use the latest advances in science to serve this promise.”
Monday marks 22 years since the attacks in New York, where two aircraft were hijacked by suicide bombers, and flown into the World Trade Centre’s Twin Towers, killing thousands.
Another hijacked flight was flown into the Pentagon, while a fourth attempt crashed in rural Pennsylvania, after passengers overpowered the attackers.
It is widely accepted the attacks were carried out by terrorist group al Qaeda, led by Osama bin Laden.