WASHINGTON – An armed man ran through the hallways of the Capitol after crashing his sport utility vehicle through a barricade Monday in the worst breach of security on Capitol Hill since a gunman killed two police officers eight years ago.

The man who led police on a chase through the building was Carlos Greene, 20, of Silver Spring, Md., said Acting Capitol Police Chief Christopher McGaffin. Greene had a loaded gun and crack cocaine, McGaffin said.

Police charged Greene with federal felony possession and assault of a police officer.

McGaffin said there would be a review of Capitol security measures.

Police officials and congressional aides said the man was tackled outside a basement office. They said he was carrying a small weapon but there were no reports of shots fired.

The incident occurred shortly after 8 a.m. EDT. Congressional aides said the man appeared to be having a seizure and was taken by ambulance to a Washington hospital.

Details remained sketchy, but construction workers and police said the man, wearing a blue ballcap, drove an SUV through a barricade at a huge construction site on the east side of the Capitol, across from the Supreme Court.

His vehicle also crashed into a water fountain on the plaza in the middle of the construction area.

One leadership aide said the SUV clipped a police vehicle parked outside the construction area, the site of a visitors center slated to open next year.

The visitors center is being built in part to provide an extra layer of security for visitors to the Capitol following the 1998 incident in which a mentally disturbed man ran through a first-floor door of the Capitol, shooting to death one police officer at the door and another inside the adjacent office of then-Majority Leader Tom DeLay.

Security around the Capitol increased significantly after that shooting, and again after the Sept. 11 attacks.

One security officer, speaking on condition of anonymity pending the official briefing, said that after abandoning the vehicle the man ran up the east front steps into the Rotunda, then down a stairway into the basement. He was captured outside an office used for distribution of American flags that lawmakers send their constituents.

The Capitol complex was closed for almost an hour before reopening for staff and tourists. –Eric Ueland, chief of staff for Senate Majority Leader Bill Frist, said that after the capture, police conducted a search through the Capitol to ensure there had been no other intruders.

Police cordoned off the vehicle, which sustained a damaged front fender, and searched it.