The Washington Monument has closed after yet another elevator malfunction.

The National Park Service says the elevator stopped for unknown reasons about halfway up the 555-foot obelisk on Tuesday afternoon. A few dozen people were evacuated, some from the elevator and some from the observation level of the monument. No one was injured.

The elevator has stopped working several times within the past year, most recently last month, when the monument was closed for three days to repair a damaged elevator control box.

The park service says technicians are on site and the monument will stay closed until they find the problem and make any necessary repairs.