OAKLAND, Calif. — Passengers cheered as the Grand Princess cruise ship pulled into port in Oakland on Monday, the first step in an unprecedented domestic operation that will require medical care and the quarantining of more than 3,000 people who may have been exposed to the novel coronavirus.

“Thank you,” shouted one passenger. Others waved at the dock workers.

Roughly five hours later, a slow line of passengers moved down the walkway as people finally disembarked. Workers in the area donned full-body protective clothing, including tan suits, scrubs, face masks and surgical hats. Tents were up next to the walkways extending from the ship to receive passengers and conduct screenings. Charter buses pulled closer to the ship, backing into parking spaces about 50 yards away and standing by.

The ship docked two days after its scheduled arrival in San Francisco, and its 3,500 passengers and crew members are set to be evaluated upon arrival. The roughly 1,100 crew members will be quarantined onboard, unless they need urgent medical care — in which case they’ll be taken to a California medical facility.

The offloading process is expected to take days, in a massive operation that will test the abilities of federal and state officials to safely contain the site of a known outbreak of covid-19, the disease caused by the coronavirus. Next, many of the exposed travelers will be transported through highly populated areas by bus and flown by chartered plane before quarantine.

California passengers will be taken to military bases within the state for quarantining — one in northern and another in southern California — while other U.S. residents will be taken to bases in Texas and Georgia. Canadians will be transported to their home country for quarantine.

Officials said Friday that 21 of the 46 people tested on the ship had the coronavirus, indicating that the illness could be spreading on the ship. Nineteen of those who tested positive were part of the crew.

Grand Princess passengers who are U.S. residents waiting to arrive back on land received an unsigned letter Monday saying they will be bused or flown “to a designated military installation,” according to a copy viewed by The Washington Post, with a final destination provided before boarding planes. All passengers would be screened for symptoms, and authorities were working to make sure that “symptomatic passengers, or passengers who require medical care” would receive that treatment in California.

The scene as the coronavirus-stricken Grand Princess cruise ship pulls into California port

March 9, 2020 | The Grand Princess cruise ship, top, idles outside the Golden Gate in San Francisco. The ship was forced to idle for days off the coast of California because of a cluster of novel coronavirus cases aboard. (Ross D Cameron/EPA-EFE/Shutterstock)

Upon arriving at a military installation, passengers will be issued quarantine orders by the Centers for Disease Control and Prevention. But, the letter said, the CDC will “reassess this quarantine order” after 72 hours and, after reviewing “the relevant data and any new information,” determine whether a passenger might be released “under less-restrictive measures.”

The U.S. Department of Health and Human Services said Sunday that passengers would be taken “to federal military installations for medical screening, covid-19 testing, and a 14-day quarantine,” adding that they would be monitored for symptoms “throughout the quarantine.” It made no mention of less-restrictive measures after 72 hours. Spokespeople for HHS and the CDC did not respond to questions Monday about the letter’s statements regarding reevaluations after 72 hours.

Vice President Pence said in a news conference late Monday that the 21 patients with covid-19 were in “proper isolation.” He added that all passengers will be tested for the coronavirus and that the 25 children on the ship are healthy.

California authorities have stressed that the ship will leave Oakland quickly and go somewhere else for the period during which crew members are quarantined onboard.

Princess Cruises said Monday that 2,016 passengers on the ship were from the United States and 406 were from 23 other countries, though it did not say which ones. The cruise line also said it did not “have further information on where Grand Princess will go” during the crew’s quarantine after all passengers are discharged.

The Canadian government said in a statement that the 237 Canadians onboard would be brought to a military base in Ontario and quarantined for two weeks. But these passengers would be screened for symptoms before boarding, the statement said, and not allowed on if they exhibit any.

“We expect a phased disembarkation process to take place over the next few days,” Capt. John Harry Smith told passengers earlier Monday, according to a recording shared with The Post. “Priority disembarkation today will be given to guests with more urgent medical needs.”

Smith also said that the cruise ship would receive additional prescription medication and that it would be distributed accordingly.

In an announcement over the ship’s loudspeakers Monday afternoon, Smith said that in addition to guests with medical needs, government officials hoped to take “some of our U.S. guests from California” off the ship as well. Smith said in his announcement, made shortly before 3 p.m., that “the first groups of individuals have begun to disembark.”

Kari Kolstoe, 60, was one of those passengers. She said she has Stage 4 neuroendocrine cancer and was originally supposed to be back in Grand Forks, N.D., in time for cancer treatment starting early this week. Kolstoe said she was worried while quarantined on the ship because of her “compromised” situation. She also dealt with being bored, frustrated and back pain caused by the cancer.

Kolstoe and her husband Paul were loaded onto a bus Monday afternoon wearing masks, but sat there for about three hours before finally driving to Travis Air Force Base, she said.

It was unclear whether she would get her treatment at the base, but she was “just glad to be off the ship,” she wrote in a text message.

Earlier in the day, tents were set up to receive passengers at the port. Two green Servpro disaster recovery trailers were in the area with labels that read, “Ready for whatever happens.” Workers wearing vests from the same company roamed the grounds. Other trailers were labeled, “California disaster medical support.”

About 20 police officers were huddling near ambulances as the ship docked. Meanwhile, dock workers wearing gloves were taping a plastic sheet atop a foldout table anticipating passengers’ arrival. The California Governor’s Office of Emergency Services had set up a makeshift support unit near the rear of the ship.

Police officers and port employees turned away reporters from the staging area for sick passengers earlier that morning. A half-dozen charter buses could be seen parked in a row. A port worker wearing a yellow vest said the buses were meant to transport passengers when they get off the ship. A truck for an event rental company could be seen entering the port. A police officer washed his hands at a portable sink that had been set up near portable bathrooms.

Two men who work in the office near the cruise ship staging area wondered whether they should be worried about exposure to the virus. Workers said the area is normally quiet.

To prepare for the ship’s arrival, federal authorities took measures including fencing off the 11-acre portion of the Port of Oakland and securing it with federal personnel, according to a news release from the California Governor’s Office of Emergency Services. Oakland city officials were not permitted inside the sealed area.

The crews set up tents to conduct medical screenings of passengers disembarking the ship, according to the office, and tests were performed by federally trained medical workers. Anyone interacting with passengers was given personal protective equipment, and port workers handling the travelers’ baggage were given their own set of gear.

Protective measures were taken with an eye toward separating potentially exposed passengers and personnel, given that the “virus transmits person-to-person when people are in proximity, that is less than six feet apart.” Officials said anyone with a cough, fever or respiratory issue would be given a surgical mask and taken off the ship via a separate gangway, and then isolated to receive medical help and remain out of the vicinity of others.

“They will not be transported to medical care with healthy passengers; they will remain isolated,” the news release said.

Bus passengers would be given face masks and briefed on social distancing, while workers would be equipped with personal protective equipment. Foreign nationals being taken off the ship would be taken to a “remote part of the Oakland International Airport,” sealed off to commercial passengers, and placed on charter flights home with protective equipment. Finally, the temporary port operation will be fully deconstructed.

“Following the completion of the mission, the Port of Oakland site will be fully remediated and decontaminated by immediately removing temporary structures and pressure washing the entire site with a bleach solution to disinfect it,” the office said.

Katie Zezima contributed to this report.