By Anna Ringstrom

STOCKHOLM (Reuters) -SAS and pilot unions were set to resume negotiations on Monday in an effort to end a two-week strike that the Scandinavian airline says threatens its existence.

Most SAS pilots in Sweden, Denmark and Norway walked out on July 4 after talks over conditions related to the carrier’s rescue plan collapsed. The parties returned to the negotiating table in the Swedish capital on July 13.

“I hope it will get solved,” Jan Levi Skogvang, one of the union officials represending SAS pilots, told reporters as he arrived for the talks on Monday.

Shares in SAS were up 11.6% at 0727 GMT as talks continued, though the stock is down nearly 70% over the past year.

Negotiations had continued through the weekend in a marathon 33-hour session without breaks.

The parties made progress but significant issues had yet to be resolved, a mediator said late on Sunday.

Long-struggling SAS needs to attract new investors and secure bridge financing, saying it must first slash costs to achieve those objectives.

Pilots employed in the 75-year-old carrier’s SAS Scandinaviasubsidiary said after talks collapsed that they would agree to limited wage cuts and less favourable terms, while SAS said the concessions offered were not enough for it to carry out a rescue plan announced in February.

Unions also demand that pilots axed during the COVID-19 pandemic are rehired at SAS Scandinavia rather than having to compete with external applicants for jobs on less attractive terms at recently created SAS Link and Ireland-based SAS Connect

For Monday, 183 SAS flights, or 57% of those scheduled, werecancelled, according to flight-tracking platform FlightAware.Pilots at SAS Link and SAS Connect are not on strike.

(Reporting by Anna Ringstrom; writing by Anna Ringstrom and Gwladys Fouche; editing by Muralikumar Anantharaman and David Goodman)