A major fire raged for several hours Thursday in the top floors and roof of the main building of the U.S. Embassy, forcing the evacuation of hundreds of employees, officials said.

Embassy spokesman James Bullock said one U.S. Marine was treated for smoke inhalation, but all other employees were evacuated without injury. Normally between 400 and 500 people are in the embassy during working hours, and the fire broke out at 10:15 a.m.James Le Viness, who works in the consular section of the embassy where hundreds of Soviets line up daily seeking visas, said the fire apparently began in an elevator shaft on an upper floor of the 10-story building and then quickly spread to the roof.

"It was really cooking," Le Viness said of the blaze. "It just spread so fast. From the time that we heard the alarm, we were out two minutes later and (by then) the smoke was just billowing."

Embassy political officer John Parker said the fire was very intense.

"I don't expect that we will be back into the embassy soon," Parker said, adding that diplomats would probably have to set up temporary offices next door in the partially completed new American Embassy compound and the nearby U.S. Commercial Office building.

Work on the main office building in the new embassy compound was stopped with the building nearly completed several years ago after American officials found extensive Soviet eavesdropping equipment. That building cannot be occupied but other facilities in the compound are being used.

Le Viness said the Soviet firefighters who responded to the alarm at the embassy Thursday seemed to lack proper equipment to fight the blaze and even had trouble connecting hoses to fire hydrants.

"They did the best they could," he said. "It isn't NYFD (New York Fire Department) equipment."