Two major cruise lines, Princess and Viking, have announced they are suspending their global operations temporarily because of the new coronavirus. Between them, the lines operate nearly 100 ships – though the majority of Viking’s fleet is small river cruises.

Princess Cruises announced Thursday morning it is voluntarily canceling sailings on its 18 ships around the world through May 10. The cruise line sails with about 50,000 passengers a day, according to a statement.

The cruise line has seen passengers and crew on two of its ships, Diamond Princess and Grand Princess, face quarantines since February after the new coronavirus spread on board. On Thursday, passengers were still disembarking from the Grand Princess in California to wait out a quarantine period on land.

The “voluntary and temporary pause” goes into effect for all departures starting Thursday; voyages that are underway and scheduled to end within five days will keep sailing their scheduled itineraries. Those that are currently sailing with return dates past Tuesday will end “at the most convenient location for guests, factoring in operational requirements,” the line said.

In a statement, the company said it was making the decision out of an abundance of caution and called the move “a proactive response to the unpredictable circumstances evolving from the global spread of covid-19.”

The cruise line’s president, Jan Swartz, said in a statement: “By taking this bold action of voluntarily pausing the operations of our ships, it is our intention to reassure our loyal guests, team members and global stakeholders of our commitment to the health, safety and well-being of all who sail with us, as well as those who do business with us, and the countries and communities we visit around the world.”

Industry giant Carnival Corp., which owns Princess Cruises as well as Carnival Cruise Line, Holland America Line, Seabourn and several other lines, has not announced whether other brands will follow suit.

Additionally, Viking Cruises, which operates a global fleet of 78 river boats and ocean cruise ships, has suspended all embarkations from Friday to April 30 in response to the coronavirus pandemic, said founder and chairman Torstein Hagen on Thursday.

In a message to future passengers, Hagen said operating a travel company during the outbreak posed “significant risk” of quarantining and screening, such has occurred with the Diamond and Grand Princess cruise ships, which became emblematic of the worldwide epidemic.

But potential exposure also prompted the suspension, Hagen said, after a river cruise passenger in Southeast Asia may have come in contact with the virus on an international flight.

“While this guest is not exhibiting symptoms, she has been placed in quarantine. Separately, the remaining 28 guests will also be quarantined,” he wrote.