“We cannot and will not remove all sailors from the ship,” Modly told Pentagon reporters. He said officials will send as many sailors off the ship as possible while still maintaining safety. He said about 1,000 have gone ashore, and that number will grow to at least 2,700 in a couple of days.

Modly and Adm. Michael Gilday, the chief of naval operations, declined to say how long the ship will be sidelined. But if crew members are required to be quarantined for 14 days, on a rotational basis, the Roosevelt could be out of duty for weeks.

The Navy leaders said that they are trying to track down any sailors who came in contact with those now ill and place them in quarantine. They said almost 1,300 sailors have been tested, and as of Wednesday, nearly 600 of those tests came back negative. Officials are awaiting more results and more testing.