The alleged gunman, Robert Pickett, a former Internal Revenue Service employee from Evansville, Ind., was taken to GW Hospital, arriving at 11:57 a.m.

Hospital officials said the man was in stable condition during a press conference in Ross Hall at about 3 p.m. Officials said they could not release personal information about the alleged gunman.

The patient suffered a gunshot wound to the leg, causing damage to his right knee that required surgery, said Yolanda C. Haywood, associate professor of Emergency Medicine at the Medical Center. He was not talking and was motionless when he arrived.

White House Press Secretary Ari Fleischer said President George W. Bush was never in any danger, but he would not confirm whether shots were fired on the grounds.

“The suspect never entered the White House grounds,” Fleischer said. “It all took place outside the gate of the White House, on public property, on a public sidewalk.”

At 11:22 a.m., the U.S. Park Police received information of a man with a gun on E Street, south of the White House. A Metropolitan Police officer engaged the man in conversation and a gunshot was fired at some point during the conversation, Park Police spokesman Rob MacLean said in a press conference.

Fleischer said Secret Service agents were on patrol when they heard shots fired near the southwestern perimeter of the White House. Within minutes of the shots, a swarm of Secret Service agents, Park Police and Metropolitan Police officers arrived on the scene, quickly locking down the White House and blocking off the area.

Bush was exercising in the residence at the time of the incident, and Vice President Dick Cheney was working in the West Wing.

“The president said that he understood he was never in any danger and he kept up what he was in the middle of,” Fleischer said.

Dan Halpert, a 24-year-old tourist from Queens, N.Y., said he was walking past the White House when he heard a popping sound.

“Everything happened so quick, you didn’t even have time to think,” Halpert said. “As soon as I heard a gunshot, the police started converging into the center area from all sorts of directions.”

Halpert said he ducked behind parked cars with several dozen other pedestrians when police told them to hit the ground and leave the area immediately.

“I’m fairly shaken up,” he said less than an hour after the incident. “It’s kind of a scary experience.”

The suspect – an accountant who sued the government after being fired from an IRS job in the 1980s – underwent a psychiatric evaluation after surgery, Haywood said. Evansville, Ind., police officers said he had no criminal record. Secret Service agents were preparing a search warrant for his home, the Associated Press reported Wednesday.

In 1995 a man scaled the White House fence with a weapon and was shot in a scuffle with a Secret Service officer. A man pulled a semiautomatic rifle in front of the White House in 1994, firing 20 to 30 rounds. Earlier that year, a Maryland man died after crashing a small plane onto the South Lawn of the White House.