Two Russians named by British authorities as suspects in the March poisoning of Sergei Skripal and his daughter Yulia travelled to Geneva at least six times in the run-up to the attack, report two Sunday newspapers.
The suspects, named as Russian military intelligence agents Alexander Petrov and Ruslan Boshirov, also stayed in Geneva for long periods, according to "SonntagsZeitung" and "Le Matin Dimanche".
This has been confirmed by several informed Swiss and foreign sources on condition of anonymity, they say.
The British authorities are now working with the Swiss Federal Intelligence Serviceexternal link to try to find out what Petrov and Boshirov were doing in Switzerland, according to the two Swiss newspapers.
"SonntagsZeitung" and "Le Matin Dimanche" also refer to a report in British newspaper The Telegraphexternal link which details how the pair travelled across Europe in the runup to the attack, reserving nine different flights to and from Geneva between November 2017 and February 2018, travelling from Moscow via Paris.
Ex-Russian spy Sergei Skripal and his daughter Yulia were poisoned with the nerve agent Novichok in Salisbury, UK, on March 4. The two were hospitalized for weeks but eventually recovered.
The case caused a massive diplomatic row between the West and Russia and is being investigated in several states.
Russia has so far denied any involvement.