Washington (CNN) Defense Secretary Mark Esper made clear to CNN that two Navy hospital ships being deployed to help respond to the coronavirus outbreak will not treat patients suffering from the virus and will take weeks to deploy.

The Pentagon also confirmed they will provide 2,000 hospital beds. New York Gov. Andrew Cuomo said Wednesday that his state alone needs an additional 50,000.

"I have directed, as the President has mentioned, the hospital ships Mercy and Comfort to be prepared to deploy to increase the nation's medical capacity and we've also alerted a variety of field and expeditionary hospitals to be prepared to deploy as well as needed," Esper said at the White House on Wednesday.

Cuomo announced Wednesday that the USNS Comfort would be docked in New York City harbor.

He called the decision to deploy the ship an "extraordinary step" because the Comfort is "literally a floating hospital."

However, the ships will not treat coronavirus patients. Instead they will be used to treat other illnesses or injuries, and free up capacity in civilian hospitals that are expected to be overwhelmed with cases of the virus. Also, the fact the Comfort is not expected to deploy for a number of weeks means it will not provide support if the number of cases and deaths spike in the near term, as many experts have predicted.

The USNS Mercy is likely to deploy sooner, though the Pentagon has not said where it will be sent.

"The Comfort, which is on the East Coast, should be ready in a couple weeks -- plus, the Mercy, which is on the West Coast, should be ready in a week and a half, two weeks, definitely before the end of this month the Mercy will deploy," Esper told CNN's Jake Tapper Wednesday.

Esper also said that the Pentagon was prepared to provide field hospitals to state authorities to also help with non-coronavirus patients.

"What we have offered up are what I mentioned -- those field hospitals, those expeditionary hospitals. Those provide the same functions as the hospital ships, we can field them fairly quickly, we can provide hospital beds and we can provide doctors, nurses, equipment all those things you need," Esper told Tapper while making it clear that those field hospitals would similarly not treat coronavirus patients.

"Again they're geared toward trauma, and what we can do is to create space in local hospitals by peeling off their trauma patients putting them through our field hospitals," Esper said, adding "we could set it up in an open field and we can process patients through there whatever makes most sense, that's most convenient for the governors, again those are conversations I'm having."

Ships receiving maintenance

The Norfolk-based Comfort and San Diego-based USNS Mercy are "currently working to complete scheduled maintenance cycles and identify necessary medical staffing to deploy as soon as possible," the US Navy said in a statement to CNN.

"The Comfort is intended to head to New York, in that area, on timing wise that's a little bit more difficult," Chief Pentagon Spokesman Jonathan Hoffman told reporters on Wednesday.

"The Mercy will be prepared and ready to go much sooner," Hoffman said, saying "they are hopefully going to be prepared to go in days not weeks" and that when it's prepared to sail, a determination will be made as to where it will go.

Each ship has a capacity for about 1,000 beds but many of their treatment areas are in open bay and would therefore be ill-suited to handling potentially contagious coronavirus patients.

"The Comfort and Mercy will not deploy to treat COVID patients but will be made available to assist with treatment of other patients in coastal locations where local health professionals are necessarily focused on a large number of COVID cases," a spokesperson for the Navy told CNN in a statement.

In addition, over 1,000 field hospital beds are being readied along with the units to man them, not counting the ships,according to Joint Staff Surgeon Brig. Gen. Paul Friedrichs, who briefed reporters at the Pentagon on Wednesday.

Staffing challenges

Another issue is staffing the two ships.

The ships are typically staffed by US Navy reservists or civilian volunteers, and staffing them could present challenges if those personnel are drawn from the civilian medical work force that is actively responding to the crisis.

Defense officials, including Esper, are cognizant of those challenges with Hoffman saying Wednesday that "staffing is an issue."

Officials say that they will seek to avoid calling up reservists and focus on active duty military medical personnel in order to avoid that issue.

"Right now we're looking at our military staffing," Friedrichs said Wednesday.