Switzerland said on Friday it had beefed up security in preparation for next week's summit between US President Joe Biden and his Russian counterpart Vladimir Putin, and had deployed thousands of troops and police in Geneva to tackle any terrorist threat.

Biden and Putin will meet at La Grange villa overlooking Lake Geneva on June 16 for their first face-to-face meeting since Biden took office in what is expected to be heated talks on issues ranging from nuclear arms control to cyberattacks.

"We are approaching a historic moment," Stefan Taimer, deputy director of the Swiss Federal Police, told reporters in the garden surrounding the 18th-century villa.

Exterior view of the eighteenth century La Grange villa overlooking Lake Geneva (Reuters)

As he spoke, an army helicopter flew by. "The terrorist threat in Switzerland and Europe is still significant. There are other threats from violent extremist groups... We are on high alert with a heavy deployment of forces."

Today, Friday, the Federal Government in Berne announced a temporary restriction of Geneva's airspace from 15 to 17 June.

Inside one of the halls of the villa "La Grange" in Geneva, which combines luxury and historical architecture (European)

Local authorities, who have erected barricades and razor wire, said they would close the city center facing the lake.

The Swiss authorities are racing against time to renovate the place that will host the upcoming summit between Putin and Biden (European).

"We didn't have time to do a renovation, we're putting in touches," said designer Federica Ort, standing on a staircase and painting the eaves near the ceiling.

A designer is putting the finishing touches on one of the halls of Villa "La Grange" (Reuters)

Despite much talk about the upcoming summit between Presidents Joe Biden and Vladimir Putin and the reliance on it to deal with thorny files, the two parties do not seem very optimistic about the results. North Atlantic Treaty Organization (NATO) before his meeting with Putin, and that he will inform the latter that Washington will not stand idly by in the face of Russia's human rights violations.

On the other hand, Putin recently criticized the US policy towards his country, especially with regard to sanctions.