Arlington National Cemetery was evacuated Wednesday morning and closed for hours because of a bomb threat.
Officials with the cemetery and Joint Base Myer-Henderson Hall combed through the entire 624-acre property for hours.
Visitors and employees left the property during the investigation.
As of 11:30 a.m., the cemetery was closed to the general public but open for funeral services. Family pass holders also were allowed to enter.
Normal operations had resumed at the cemetery by 3 p.m., officials said. No information was released on how the threat was made or what investigators determined.
Cemetery superintendent Kate Kelley said officials take security seriously.
"I would especially like to thank our family members for their patience during this time and our employees for continuing to support the funeral services today," Kelley said in a statement.
The cemetery was set to remain open until 7 p.m., its normal closing time.