Italian authorities have urged pilgrims to stay away from central Rome, saying that due to huge crowds any newcomers would have no chance of seeing Pope John Paul's funeral on Friday.
The head of crowd control for the funeral,Guido Bertolaso, told reporters Wednesday that well over one million people had already flocked to the city.
He asked pilgrims to go to a special camp on the outskirts of the city.
Officials also announced plans to cut off the line of mourners at 10 p.m. local time (20 hours UTC) to give those already waiting a chance to pay their last respects before Saint Peter's Basilica closes Thursday night, ahead of the pope's funeral.
Vatican officials estimate more than two million people will have filed past the pope's body before they close the Basilica.
Meanwhile, Roman Catholic cardinals, who will choose a new pope, have set April 18th as the date for the start of their closed-door deliberations.
A Vatican spokesman told reporters on Wednesday that a special Mass will precede the conclave and then the cardinals will meet to begin the process of electing a successor to the late pope.
Rome is tightening security because John Paul's funeral on Friday is drawing leaders from all over the world, among them President Bush.