Switzerland said Tuesday that it had decided to block the participation of Russia's air display team at a military show in the neutral nation due to the Ukraine crisis.

The Russian Knights, an aerobatic squadron who fly Su-27 fighters, had been due to take part in the Air14 festival starting later this month.

"Even in times of crisis it is important to maintain contacts," the Swiss defence ministry said in a statement.

"Nevertheless, military contacts are of a special nature and in the present circumstances it would be preferable to show restraint," it said, adding that the Russian Knights' participation "would not be appropriate".

The decision was made after consultations with the Swiss foreign ministry, it said.

The Air14 show is scheduled to take place on the weekends of August 30-31 and September 6-7 at a military base in Payerne in western Switzerland.

As well as marking the centenary of the Swiss air force, the show will also celebrate the 50th anniversary of the country's own display team, the Patrouille de Suisse.

Unlike the European Union and the United States, Switzerland has been wary of imposing economic sanctions against Russia over Ukraine.

The traditionally neutral Switzerland, which is not a member of the EU, has nonetheless placed scores of individual Russian officials, pro-Moscow separatists from Ukraine and related firms and entities on a blacklist.

The stated aim is to ensure that the Swiss financial sector is not used to duck sanctions introduced by other countries.

As the current chair of the Organisation for Security and Cooperation in Europe, Switzerland is also at the centre of efforts to broker a settlement to the crisis.