NYPD Commissioner Raymond Kelly reassured the city Thursday that officers are prepared to protect Pope Benedict XVI during his visit.

According to Kelly, about 52,000 people will pack Yankee Stadium for a special Mass and other ticket holders will flood Manhattan's ground zero and St. Patrick's Cathedral during the pope's trip from April 18 to April 20.

Kelly also said thousands more New Yorkers will try to catch a glimpse of the pontiff, all presenting the NYPD's "biggest security challenge ever."

Non-ticket holders' best opportunity to see the pope will likely be along Fifth Avenue as the pope mobile makes its way toward 70th Street from St. Patrick's.

"The world has changed. It's a post-9/11 event, so we have to factor in other considerations," Kelly said. "But I can assure you that we believe ? we've done everything to protect the pontiff here in New York."

Police said several major roadways would close during the visit, but added that the Major Deegan Expressway and the 4 subway line would remain open during the Yankee Stadium Mass.News 12 Brooklyn will have live coverage throughout the pope's visit.

Archdiocese of New York