Pope Francis was due late Friday to lead the torchlight Way of the Cross procession at Rome's Colosseum amid a high-security lockdown after the deadly Brussels terrorist attacks.
The area around the 2,000 year-old monument will be cordoned off and visitors will be screened at various security checkpoints before being allowed into the Colosseum area, police said.
Portable and fixed metal detectors will be used as well as bomb squads with sniffer dogs, according to police.
The security measures, including more surveillance on public transport in the capital over Easter weekend, are aimed at guaranteeing maximum safety conditions for pilgrims and other tourists, Rome police headquarters said.
There is no specific terrorist threat against Italy, premier Matteo Renzi said after Tuesday's bombings of Brussels international airport and subway system that killed 32 people and injured 300, claimed by the Islamic State jihadist group.
But the capital's top government official Franco Gabrielli warned on Friday that Italy is "a possible target of Islamist terrorism".
"The threat is real," he said.
More security forces have been deployed in Rome, this week, he announced on Wednesday.
"We have increased the law enforcement presence and are assessing military contingents," Gabrielli said.
