The USNS Mercy, which docked in the Port of Los Angeles, will quickly become the city's largest hospital with 1,000 beds.

It will not receive coronavirus patients, but instead take patients with a wide range of other conditions or injuries in order to free up facilities on land.

The 894-foot (272-meter) Mercy, a converted oil tanker, has 15 patient wards and blood bank capacity of 5,000 units.

Governor Gavin Newsom, speaking at a joint press conference after touring the vessel with Mayor Eric Garcetti, said the ship will play a key role as California braces for a surge in COVID-19 infections that could require 50,000 hospital beds statewide in the next six to 10 weeks.

Los Angeles is "on track within a week to be aligned with where New York City currently is," he said, referring to America's most populous city which has almost half of US's 100,000-plus coronavirus cases.

California officials lobbied intensely for the ship to come to Los Angeles, overriding a competing claim from northwestern Washington state which is also badly affected but less populous.

According to a tracker maintained by Johns Hopkins University, California has more than 4,000 confirmed cases of coronavirus, with 90 deaths.

Los Angeles alone reported nine new deaths and over 400 new cases on Thursday.

Nationwide, there have been 1,544 deaths.

The Mercy's arrival precedes the passage of its sister ship, the Comfort, to New York.