After being struck by lightning near the White House, four people were critically injured.
The two men and two women were killed in Lafayette Park in Washington DC during a violent storm, according to fire officials.
Because of the park's proximity to the US presidential residence, members of the secret service were among the first to assist the victims.
The identities of those injured have yet to be determined.
On Thursday evening, lightning struck four people near a tree near the fence that surrounds the White House complex.
"All four were suffering from critical, life-threatening injuries," according to a statement from DC Fire and EMS. "We were able to quickly treat and transport all four patients, who were all transported to nearby hospitals."
Officials are still trying to figure out if they knew each other and what they were doing before the lightning strike.
Following the incident, a portion of the park remained closed, with emergency personnel on the scene.
On Thursday evening, the National Weather Service issued a thunderstorm warning for the area.
Lafayette Square, located directly north of the White House, is a seven-acre public park. It is frequently crowded with visitors, particularly during the summer.