Residents of Moscow reported problems using satellite navigation in cars and on mobile devices this week, as the Kremlin stepped up security for the annual Victory Day parade on Red Square on May 9.
Maps from the GPSJam website showed a "high level" of Global Positioning System interference across Moscow on Wednesday and Thursday, the day of the main rehearsal, meaning over 10% of aircraft overhead recorded low navigation accuracy.
One Reuters journalist living in Moscow who tracks his bike journeys on a smart watch found on Thursday that it only began recording when he left the city centre for the suburbs.
Another resident said a taxi driver had told them that satellite navigation apps had been "going crazy" all day.
With numerous drone attacks and acts of sabotage being reported in Russia in connection with the conflict in Ukraine, security in the capital had already been tightened for the parade, even before videos emerged on Wednesday appearing to show two drones being shot down directly above the Kremlin citadel.
Kyiv and Washington both denied Moscow's accusations that they were behind the incident, which the Kremlin called an attempt to assassinate President Vladimir Putin.
Russia has not officially acknowledged the disruption to navigation systems, but has reportedly used jamming technology in the past to block satellite signals that may be used by drones.
Several Russian regions have scaled back or cancelled Victory Day events, citing concerns that pro-Ukrainian saboteurs could target the proceedings.
Ukraine has denied being involved in attacks inside Russia, blaming them on Russian anti-government partisans or "false flag" operations orchestrated by Moscow itself.
(Reporting by Reuters; Writing by Caleb Davis; Editing by Kevin Liffey)
