NEW YORK – A five-alarm fire damaged the Cathedral of St. John the Divine in upper Manhattan on Tuesday, gutting the gift shop and severely damaging two priceless 17th-century tapestries at the largest church in the United States.

The cause had not yet been determined by evening.

Firefighters were called to the cathedral before 7 a.m. after a janitor smelled smoke. By the time they arrived, the gift shop had burst into flames. Within an hour the fire had grown into a fierce blaze that filled the cathedral with smoke and sent a gray plume rising above Manhattan’s Upper West Side.

“The whole thing was just a huge orange ball of flames,” said Dorothy Pappadokas, who plays the cathedral organ and first noticed the fire from her bedroom window. “It was going up the height of the cathedral walls.”

Early this afternoon firemen still were climbing around the outside of the French Gothic structure and spraying out small pockets of fire. Charred remains of the gift shop’s roof lay on the Cathedral School’s playground and damaged kneelers lay strewn on the broad front steps. The smoke that had filled the nave was mostly cleared, and firemen had pumped out the several inches of water flooding the church floor, said cathedral spokesman Gere Farrah. The 150 stained-glass windows, including a 40-foot Great Rose Window, appeared to be unhurt.

“This would have been a major catastrophe” had the fire not been controlled, said Edward Dennehy, deputy chief of the fire department’s third division.

Workers had laid out the damaged tapestries on the cathedral floor and were attempting to assess damage. They are part of a set of 12 tapestries commissioned by the Barberini family and woven in the Vatican.

The cathedral, begun in 1892 and still under construction, is a major New York institution that has grown as a community center since the attacks on the World Trade Center. Located within a block of Columbia University and St. Luke’s-Roosevelt Hospital Center, the church hosts a half-million visitors a year.

Since the Sept. 11 attacks, the cathedral has held daily vigils and a steady flow of memorial services that continued through last week. Close to 5,000 people attended one service dedicated to victims who died at Windows on the World restaurant.

“After September 11th, a lot of people came here to pray,” said Sister Faith Margaret, who lives nearby and frequently attends events at the church. “It’s one more tragedy.”

The cathedral school closed Tuesday and students were sent home. But the church kept its homeless shelter open and moved its meal service to another church.

Cathedral officials did not know whether or where they would hold upcoming holiday events. The cathedral had scheduled a steady stream of religious services and musical events including a Friday performance of Handel’s “Messiah.” Nearby synagogues and churches already were offering space Tuesday afternoon to hold those services; cathedral officials hope to be back in St. John’s for Christmas Eve.

“I have always thought of it as so large and indomitable,” said James Kowalski, who will become dean of the church in March. “But what is these days?”