Crans-Montana (Switzerland) (AFP) - All of Switzerland will mark a national day of mourning Friday for the dozens of mostly teenagers killed when fire ravaged a ski resort bar crammed with New Year revellers.

Just over a week after the tragedy at the Le Constellation bar in Crans-Montana, which left 40 dead and 116 injured, the wealthy Alpine nation will come to a standstill for a minute of silence at 2:00 pm (1300 GMT).

A chorus of church bells will then ring throughout the country.

The moment of silence will stand as a “testament to the shared grief felt by the entire nation with all the families and friends directly affected”, the Swiss government said in a statement.

At the same time, a memorial ceremony for the victims will be held in Martigny, a town about 50 kilometres (31 miles) down the valley from Crans-Montana, which had been rendered all but inaccessible by a large snowstorm.

Inhabitants of the plush ski resort town will meanwhile be able to watch the ceremony as it is livestreamed to large screens, including at the congress centre that for days after the tragedy accommodated families seeking news of missing loved ones.

- Among ‘worst tragedies’ -

A memorial that has sprung up in front of the bar, loaded with flowers, candles and messages of grief and support, was covered in an igloo-like tarp Thursday to protect it from the heavy snowfall.

Swiss President Guy Parmelin, who has declared the fire “one of the worst tragedies that our country has experienced”, will be joined for the ceremony by his French and Italian counterparts, whose countries lost nine and six nationals respectively in the fire.

Top officials from Belgium, Luxembourg, Serbia and the European Union were also due to participate in the ceremony.

Most of those impacted by the inferno at Le Constellation were Swiss, but a total of 19 nationalities were among the fatalities and the wounded.

Half of those killed in the blaze were under 18, including some as young as 14.

Of those injured, 83 remain in hospital, with the most severely burned airlifted to specialist centres across Switzerland and abroad.

Prosecutors believe the blaze started when champagne bottles with sparklers attached were raised too close to sound insulation foam on the ceiling in the bar’s basement section.

Experts have suggested that what appeared to be highly flammable foam may have caused a so-called flashover – a near-simultaneous ignition of everything in an enclosed space, trapping many of the young patrons.

Video footage which has emerged from the tragedy shows young people desperately trying to flee the scene, some breaking windows to try to force their way out.

On Tuesday, municipal authorities acknowledged that no fire safety inspections had been conducted at Le Constellation since 2019, prompting outrage.

- ‘Staggering’ -

The investigation underway will seek to shed light on the responsibilities of the authorities, but also of bar owners Jacques and Jessica Moretti.

The French couple, facing charges of manslaughter by negligence, bodily harm by negligence and arson by negligence, have been called in for questioning on Friday, sources close to the investigation told AFP.

The pair, who have not been detained, said in a statement Tuesday that they were “devastated and overwhelmed with grief”, and pledged their “full cooperation” with investigators.

They will need to answer numerous questions about why so many minors were in the bar, and whether fire safety standards were adhered to.

There has been much focus on the soundproofing foam, which, according to photos taken by the owners, had been added during renovations in 2015.

A video filmed by a member of the public, screened Monday by Swiss broadcaster RTS, showed that the danger was known years ago.

“Watch out for the foam!”, a bar employee said during 2019 New Year’s Eve celebrations, as champagne bottles with sparklers were brought out.

“This video is staggering,” Romain Jordan, a lawyer representing several affected families, told AFP, saying it showed “there was an awareness of this risk – and that possibly this risk was accepted”.