Bush is scheduled to arrive Friday night from Poland and the following day plans to make a courtesy call on the president of Italy, meet with Pope Benedict XVI at the Vatican and hold a joint news conference with Premier Romano Prodi.
Italian officials said the president's stop in Trastevere, a picturesque neighborhood of narrow streets and alleys viewed by some as a security risk, will go ahead as planned.
Achille Serra, the prefect or top government official in Rome, said "thousands" of police would be on duty between Bush's arrival and his departure for Albania on Sunday morning. But he insisted that the city "will not be sealed off."
Two demonstrations are planned in Rome, and Serra said protesters who have their faces covered, or are carrying sticks or weapons would be barred from taking part.
Until Serra confirmed the details, it had been unclear whether Bush's tour of the Basilica of Santa Maria in Trastevere and participation in a round-table in the nearby headquarters of the Roman Catholic peace group, the Community of Sant'Egidio, would go ahead.
Serra, briefing journalists on security, said many of the concerns on the Trastevere stop centered on getting Bush's motorcade through the narrow streets. Parking and private car traffic will be barred until the stop is over.