Norwegian Cruise Line Holdings (NASDAQ:NCLH), parent company of the Norwegian Cruise Line, Oceania Cruises, and Regent Seven Seas Cruises brands, announced late Tuesday that it is extending its suspension of all cruises scheduled to embark between Aug. 1 and Sept. 30 -- with the sole exception of its "Alaska Itineraries" departing from Seattle in September.

Furthermore, citing "travel and port restrictions," Norwegian noted that "select voyages" departing from Canadian and New England ports will be canceled through the month of October.

Cruise liner sailing past icebergs

Image source: Getty Images.

Norwegian had last updated its cruise schedule May 20, when it announced an "operations pause" through July 31.

The company noted that it "will continue to work in tandem with the U.S. Centers for Disease Control and Prevention," and other authorities "to ensure the health, safety and security of guests, crew and the communities visited."

The CDC's no-sail order is currently set to expire on July 24 and has not been extended. Absent an extension of that order, one would ordinarily expect Norwegian Cruise to be able to resume sailing by August at the latest (as it had previously implied). Norwegian did not explain in its press release why it is preemptively extending its own suspension of operations in the absence of an order to this effect from the CDC, and moreover, extending the suspension by two additional months.

Norwegian Cruise Line Holdings stock climbed nearly 5% in ordinary-hour trading Tuesday, mirroring gains in the broader S&P 500. After its announcement about the cancellations of additional cruises, however, Norwegian stock turned around and sank as much as 12% in after-hours trading.