Two people have been shot at the U.S. Holocaust Museum in downtown D.C., CNN is reporting. So far, no motive has been reported and details are still sketchy. It looks like a security guard and the gunman are the two people who were shot. Two men have reportedly been transported to local hospitals.

Sgt. David Schlosser from the U.S. Park Police just gave a press conference — he said a man entered the museum just before 1 p.m. today with a long gun (they aren’t sure if it’s a rifle or not). The man fired upon a security guard in the museum, at which time they exchanged fire — a couple of other security guards may have also fired at the gunman.

The U.S. Holocaust Museum is located at 100 Raoul Wallenberg Place SW, near Independence Ave. and 14th Street SW. The area around the museum is currently closed to all traffic.

1:57 p.m. The Post is reporting that three people were shot, but that doesn’t match with the U.S. Park Police account.

2:09 p.m. The AP says a third person may have been injured by broken glass. There’s also a report that the shooter may have been elderly: “Authorities have not identified the man, who was reported to be born in 1920.” That would make the shooter 89 years old.

The U.S. Holocaust Museum has put out a statement that the museum will be closed for the remainder of the day, but expects to open tomorrow. The museum also confirmed that two other guards inside the building did indeed return fire with the gunman. Those other two guards were not injured.

2:24 p.m. WJLA provides this chilling account:

David Unruh, a tourist from Kansas, was in line with his family on the main floor of the museum when he heard what sounded like “five, or maybe six” gunshots.

“People started yelling, ‘Hit the floor! Hit the floor.'” Unruh said.

After a couple of minutes, a museum employee told everyone to evacuate the building, Unruh said.

2:30 p.m. NBC News is reporting that the suspected gunman has been identified as James Wenneker von Brunn of Maryland, born 1920, who has ties to white supremacist groups. The American Prospect’s Dana Goldstein has more on his biography and affiliations with hate groups.

2:47 p.m. Mayor Fenty is starting a press conference now. He says the shooting took place immediately inside the entrance of the museum. Fenty says the shooter is in critical condition, and the security guard, whose name is still being withheld, is in grave condition.

D.C. Police Chief Cathy Lanier says there was an off-duty MPD officer nearby who entered the museum shortly after the shooting and rendered aid to the victims. She declined to confirm the shooter’s identity, but did say he appeared to have been acting alone, that he was a “lone gunman” with what appears to have been a rifle.

4:00 p.m. WTOP has learned from Federal law enforcement sources that Von Brunn is a convicted felon. “He had been convicted of bringing weapons into the Federal Reserve and served time in a federal penitentiary.”

4:14 p.m. WJLA is reporting that the Holocaust Museum guard shot by Von Brunn has died of his injuries. “He was taken to George Washington University Hospital, where he died from his injuries, high level D.C. police sources told ABC 7’s Jennifer Donelan. Sources say the gunman remains in critical condition at George Washington University Hospital.”

4:32 p.m. The deceased guard’s name is Stephen Tyrone Johns, and he had worked at the museum for six years.