Air France-KLM shares have plunged more than 8 percent in the wake of the airline's warning that weak demand on several long-haul routes and other factors would wipe hundreds of millions off profits this year.

Shares in Europe's largest airline were down 8.2 percent at 7.63 euros in late Friday trading on the Paris stock exchange.

In a statement late Thursday, Air France-KLM said a combination of factors, including weak demand, higher costs from a crippling pilots' strike, and new tax rules would strip an additional 200 million euros ($250 million) from earnings before interest, tax, depreciation and amortization this year, well above the 500 million-euro forecast it made three months ago.

Air France-KLM said it would take additional cost-cutting measures and make "a significant scale back" in investments.