( CNN ) -- Residents in Seattle , Washington , were shaken Tuesday afternoon by what sounded like explosions after two F-15s were dispatched in response to a report of a small plane that entered restricted airspace where President Barack Obama was campaigning for Sen. Patty Murray . The rumblings -- caused by sonic booms from the jets -- rattled buildings , windows and nerves in the Puget Sound region , according to CNN affiliate KIRO . Viewers of the affiliate from as far away as Tacoma -- about 40 miles south of Seattle -- reported hearing the booms . Dozens of residents called the city 's 911 system , causing it to shut down in some areas for about an hour due to the flood of calls , Ed Troyer , a spokesman for the Pierce County Sheriff 's Department told KIRO . `` Many house and car alarms have been set off that we will not be able to respond to , '' Troyer told the affiliate . The jets were launched out of Portland , Oregon , and `` were on afterburners the whole time , '' Allen Kenitzer of the Federal Aviation Administration told CNN . The plane in question -- identified by the FAA as a Cessna 180 -- left the temporarily restricted airspace before the jets intercepted it , said John Cornelio of the North American Aerospace Defense Command ( NORAD ) . The pilot of the plane later landed it near Lake Washington , Kenitzer said . The incident is under investigation . CNN 's Patrick Oppmann and Adam Levine contributed to this report .
Dozens of western Washington residents reported feeling the rumblings . The jets were scrambled in response to a plane that entered restricted airspace . President Barack Obama was in the region Tuesday . The plane left the restricted airspace before it was intercepted .