The GPS system of European Commission President Ursula von der Leyen's airplane was jammed while en route on Sunday to Bulgaria, where it landed safely, an EU spokesperson said on Monday, confirming earlier media reports.

"We can indeed confirm that there was GPS jamming, but the plane landed safely in Bulgaria. We have received information from the Bulgarian authorities that they suspect that this was due to blatant interference by Russia," the spokesperson said.

The Russian government did not immediately reply to a request for comment.

The EU gave no further details, but the spokesperson said the incident would reinforce the bloc's "unshakable commitment to ramp up defence capabilities and support for Ukraine" against Russia's three-and-a-half-year-old invasion.

In a statement, Bulgaria's government said the GPS signal was lost as von der Leyen’s plane approached the southern city of Plovdiv, prompting air traffic controllers to switch to ground-based navigation systems to ensure a safe landing.

The incident occurred while von der Leyen was on a four-day tour to EU member states that border Russia.

"There she has seen first-hand the everyday challenges of threats coming from Russia and its proxies," the commission spokesperson said.

"The EU will continue to invest in defence spending and in Europe's readiness even more after this incident."