An anti-corruption protester was arrested after he landed his mini helicopter on the US Capitol lawn and piloted it through Washington’s no-fly zone, triggering a national security investigation and shocking bystanders. The pilot, Douglas Hughes, was detained and illegal transport charges are pending against him, US Capitol Police said.

The Federal Aviation Administration (FAA) said it is investigating the incident along with other US authorities, adding that the pilot was not in touch with air traffic controllers while in the air. “The FAA did not authorise him to enter restricted airspace,” the agency said in a statement.

Hughes is from Florida and was conducting civil disobedience to call for campaign finance reform, according to the Tampa Bay Times, which had interviewed and filmed him prior to his audacious flight.

Air space is severely restricted around Washington landmarks, including the White House and the Capitol, which houses the US Congress whose 535 lawmakers were in session at the time.

A bomb squad inspected the gyrocopter, which landed a few hundred metres from the Capitol, but found nothing hazardous. It was cleared from the grounds hours later. Authorities reportedly put the building on temporary lockdown, although it was not evacuated. Iraq’s Prime Minister Haider al-Abadi was in the Capitol at the time for a meeting with senators.

The gyrocopter typically cruises at 105 kilometres an hour, with flight times of no more than 90 minutes. No airport is required for take-off and a rear propeller is used for thrust.