As Harry S. Truman used to say, the buck stops at the White House. Now workers at the New Post Office building can say the same thing.

A young deer, apparently from Rock Creek Park, drew curious crowds yesterday morning when it took an impromptu tour of downtown Washington, eventually injuring itself and becoming trapped at the postal building. Rescuers later took the animal to the National Zoo hospital, where it was being treated last night.

The grayish-brown Virginia whitetail deer was first spotted snooping around outside a White House fence. But by the time the Secret Service arrived, the deer had vanished.

No one seems to know exactly how the animal ended up in downtown Washington during the rush hour.

"He {probably} was just wandering down Rock Creek Park and got disoriented. He probably got to be excited and turned around and ended up down there," said Mitchell Bush, head veterinarian at the National Zoo.

Officials say deer aren't uncommon in this area. Deer sightings in Rock Creek Park have become more frequent in the last few years, said Bob Ford, a resource manager at the park.

"I suspect we have more than 10 {deer} at this point. The exact number is hard to say," he said. "They {the sightings} used to be sporadic; now they're frequent."

The deer that came downtown yesterday walked through morning traffic to a grassy area inside a courtyard at the Ariel Rios building, near the Internal Revenue Service at 12th Street and Pennsylvania Avenue NW.

Officers from the Federal Protective Service, which guards government buildings, said the deer panicked and jumped over a wall about four feet high and into a concrete ditch next to the postal building.

The trapped deer attracted a crowd. Office workers peered out of windows and crowded into stairwells to sneak a peek. Some cried.

"I just came out here to find out why this poor thing is bleeding to death," said Sheila Fitzgerald, a Bureau of Alcohol, Tobacco and Firearms employee, in a wobbly voice. "I love animals. I just can't stand to see him suffer."

Others took it all much more lightly.

"What are you going to do with the meat?" shouted Robert Lee, a Government Services Administration electrician. "I'll have a leg of deer in one hand and greens and some good old potato salad in the other."

Zoo workers arrived with a dart gun and shot anesthetics into the deer's right flank about 10:30 a.m. The buck, which was bleeding from the mouth, was taken away on a stretcher and driven with a police escort to the National Zoo hospital, where he was reported in "guarded" condition last night.

Bush said about a dozen stitches closed a gash on the animal's back. The deer also cut his mouth when it fell and had four injured vertebrae. Doctors are watching the approximately 2-year-old animal for signs of internal injuries.

As for a missing antler, Bush said, "I heard about 16th-hand that he broke it off in a fence at the White House. They shed them every year anyway. He'll grow one back next year."

Officials said that if all goes well, the buck will be taken to a wildlife rehabilitation center, where he will remain before being returned to a natural habitat.