Prime Minister Theresa May has ordered a full public inquiry into the fire that engulfed a west London block of flats, killing at least 17 people.
That figure is expected to rise, as fire chiefs do not expect to find any more survivors in the burnt-out Grenfell Tower in north Kensington.
The PM said people “deserve answers” as to why the fire spread so rapidly.
The first victim has been named by the Syria Solidarity Campaign as Syrian refugee Mohammed Alhajali, 23.
In a statement, the organisation said the civil engineering student was in a flat on the 14th floor, on the phone for two hours with a friend in Syria.
He was trying to get through to his family while he was waiting to be rescued.
The group said: “Mohammed bid his friend goodbye, saying that the fire had reached him. He asked his friend to pass on the message to his family…
“Mohammed undertook a dangerous journey to flee war and death in Syria, only to meet it here in the UK, in his own home.
“Mohammed came to this country for safety and the UK failed to protect him.”
His older brother, Omar, lost him on the way out and survived, the organisation said.
Earlier, Mrs May, who made a brief, private visit to the scene, said: “[The emergency services] told me that the way this fire had spread and took hold of the building was rapid, it was ferocious, it was unexpected.
“So it is right that, in addition to the immediate fire report that will be produced and any potential police investigation, that we do have a full public inquiry to get to the bottom of this.”
Labour leader Jeremy Corbyn also visited the site, telling community leaders “the truth has to come out”.