COPENHAGEN — Low-cost carrier Norwegian Air Shuttle has rejected a takeover offer from British Airways’ parent company.

Norwegian Air Shuttle says its board “unanimously rejected” the offer because it “undervalued NAS and its prospects”. No financial details were disclosed.

The board said Friday it “remains fully committed to delivering on its stated strategy, for the benefit of all NAS shareholders.”

Shares in Norwegian Air slumped 10 per cent Friday, giving it a market value of around 12 billion kroner ($1.5 billion).

Last month, International Airlines Group said it acquired 4.61% of Norwegian Air “to establish a position from which to initiate discussions, including the possibility of a full offer for Norwegian.”

Norwegian Air has disrupted the long-haul market with low-cost offers, including a 99-pound ($140) ticket from Edinburgh to New York.