Swiss President Guy Parmelin was joined by his counterparts, Sergio Mattarella of Italy and Emmanuel Macron of France, at the memorial service in Martigny, a few kilometers southwest of Crans-Montana in the Alps. The total number of participants is estimated at around 1,000, reports the APA news agency.
Swiss television broadcast the service live as church bells rang across the country at 2 p.m., and the ceremony observed a minute's silence.
40 people died and well over 100 were injured in the fire that broke out at the popular bar Le Constellation on New Year's Eve. The bar had not been inspected for fire safety in years, and the owners are suspected, among other things, of manslaughter.
The two owners were scheduled to attend an initial court hearing in the Swiss canton of Valais on Friday, APA reports.
