Italy's Culture Minister Alessandro Giuli ordered the closure of the Colosseum to be extended until Thursday as a mark of respect after a worker was killed overnight in an accident.
Andrea Moretti, a 22-year-old technician, died after falling several metres while installing a new lighting system inside the ancient Roman arena.
Built 2,000 years ago, the Colosseum was the biggest amphitheatre in the Roman Empire, used to host gladiator fights, executions and animal hunts. It is Italy's most visited tourist attraction.
"The news of the tragic death of Andrea Moretti, a skilled worker who died overnight ... has deeply shocked and saddened us," Prime Minister Giorgia Meloni said.
Giuli also ordered the suspension of all construction and maintenance work at the Colosseum until further notice.
Initially, only a partial closure of the monument was announced, but this drew protests from Italy's biggest union, the CGIL.
"Humanity comes before tourists," said Natale di Cola, the CGIL's Rome chief, adding that the union was calling on Giuli to explain all the circumstances surrounding Moretti's accident.
The incident comes less than a year after the death of a Romanian worker who was trapped for hours under the rubble of a partially collapsed medieval tower near the Colosseum last November.
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